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THE   FORMATION 

OF 

VEGETABLE    MOULD 

THROUGH   THE 

AOTIOI^  OF  WOEMS. 


THE  FOEMATION 


VEGETABLE  MOULD, 


THROUGH   THE 


ACTIOIT    OF    WOEMS, 


WITH 


OBSERVATIONS   ON  THEIR  HABITS. 


CHARLES    DARWIN,   LL.D.,   F.R.S.    T 


WITH  ILL  USTRA  TJONS. 

BOSTON  COLLFGK  LIBRARY 
CHE8TNUT  HILL,  MA8S. 

NEW   YORK  : 
D.  APPLETON  AND   COMPANY, 

72  FIFTH  AVENUE. 
1897. 


Authorized  Edition. 


6til51 


CONTENTS. 


INTRODUCTION T;iiS,e  1-7 


O" 


CHAPTER  I. 

HABITS   OF   WORMS. 

Nature  of  the  sites  inhabited — Can  live  long  under 
water — Nocturnal — Wander  about  at  night — Often 
lie  close  to  the  mouths  of  their  burrows,  and  are 
thus  destroyed  in  large  numbers  by  birds — Structure 
— Do  not  possess  eyes,  but  can  distinguish  between 
light  and  darkness— Eetreat  rapidly  when  brightly 
illuminated,  not  by  a  reflex  action — Power  of  atten- 
tion— Sensitive  to  heat  and  cold — Completely  deaf 
— Sensitive  to  vibrations  and  to  touch — Feeble 
power  of  smell — Taste — Mental  qualities — Nature 
of  food — Omnivorous — Digestion — Leaves  before 
being  swallowed,  moistened  with  a  fluid  of  the 
nature  of  the  pancreatic  secretion — Extra-stomachal 
digestion  — Calciferons  glands,  structure  of — Cal- 
caieous  concretions  formed  in  the  anterior  pair  of 
glands — The  calcareous  matter  primarily  an  excre- 
tion, but  secondarily  serves  to  neutralise  the  acids 
generated  during  the  digestive  process  .     8-54 


IV  CONTENaS. 

CHAPTER  11. 

Habits  of  worms — contiuued. 

Manner  in  which  worms  seize  objects — Their  power  of 
biintion — The  instinct  of  plugging  up  the  mouths  of 
their  burrows — Stones  piled  over  the  burrows  — 
The  advantages  thus  gained — Intelligence  shown  by 
worms  in  tbeir  manner  of  plugging  up  their  burrows 
■r— Various  kinds  of  leaves  and  other  objects  thus 
used — Triangles  of  paper — Summary  of  reasons  for 
believing  that  worms  exhibit  some  intelligence — 
Means  by  which  they  excavate  their  burrows,  by 
pushing  away  the  earth  and  swallowing  it — Earth 
also  swallowed  fur  the  nutritious  matter  which  it 
contains — Depth  to  which  worms  burrow,  and  the 
construction  of  their  burrows — Burrows  lined  with 
castings,  and  in  the  upper  part  with  leaves — The 
lowest  part  paved  with  little  stones  or  seeds — 
Manner  in  which  the  castings  are  ejected — ^Tho 
collapse  of  old  burrows — Distribution  of  worms  — 
Tower-like  castings  in  Bengal — Gigantic  castings 
on  the  Kilgiri  Mountains — Castings  ejected  in  all 
countries       .  .  ...  .     Page  55-128 

CHAPTEE  III. 

THE   AMOUNT   OF   FINE   EARTH   BROUGHT   UP  BY  WORMS 
TO    THE   SURFACE. 

Rate  at  which  various  objects  strewed  on  the  surface  of 
grass-fields  are  covered  up  by  the  castings  of  worms 
— The  burial  of  a  paved  path — The  slow  subsidence 
of  great  stones  left  on  tne  surface — The  number  of 
worms   which    live    within    a    given    space — The 


CONTENTS.  V 

weight  of  earth  ejected  from  a  burrow,  and  from  all 
tho  burrows  within  a  given  space — The  thickness 
(f  tho  layer  of  mould  which  the  castings  on  a  given 
space  would  form  within  a  given  time  if  uniformly 
spread  out — The  slow  rate  at  which  mould  can 
increase  to  a  great  thickness — Conclusion 

Pagre  129-175 


"&'■ 


CHAPTER  IV. 

THE    TAJ  IT   WHICH    WORMS   HAVE   PLAYED    IN   THE 
BURIAL   OF   ANCIENT   BUILDINGS. 

The  accumulation  of  lubbish  on  the  sites  of  great  cities 
independent  of  the  action  of  worms — Tho  burial  of 
a  Eoman  villa  at  Abinger — The  floors  and  walls 
penetrated  by  worms — Subsidence  of  a  modern 
pavement — The  buried  pavement  at  Beaulien  Abbey 
— Eoman  villas  at  Ched worth  and  Brading — The 
remains  of  the  Eoman  town  at  Silchester — Tho 
nature  of  the  debris  by  which  the  remains  are 
covered — The  penetration  of  the  tesselated  floors 
and  walls  by  worms — Subsidence  of  the  fioors — 
Thickness  of  the  mould — The  old  Eoman  city  of 
Wroxeter — Thickness  of  the  mould — Depth  of  tho 
foundations  of  some  of  the  buildings — Conclubion 

17G-22D 

ghapt:se  y. 

THE  ACTION   OF   WORUS   IN  THE  DENUDATION   OF 
THE  LAND. 

Sviience  of  the  amount  of  denudation  which  the  sand 
Las  undergone — Subaerial  denudation — The  deposi- 
tion of  dust — Vegetable  mould,  its  dark  coloar  an.^ 


vi  CONTENTS. 

fine  texture  largely  due  to  the  action  of  worms— 
j'he  disintegration  of  rocks  by  the  humus-acids — • 
Similar  acids  apparently  generated  within  tlie 
bodies  of  worms — The  action  of  these  acids  facilitated 
by  the  continued  movement  of  the  particles  of  earth 
— ^A  thick  bed  of  mould  checks  the  disintegration 
of  the  underljdng  soil  and  rocks — Particles  of  stone 
worn  or  triturated  in  tbe  gizzards  of  worms — 
Swallowed  stones  serve  as  millstones — The  levigated 
state  of  the  castings — Fragments  of  brick  in  the 
castings  over  ancient  buildings  well  rounded.  The 
triturating  power  of  worms  not  quite  insignificant 
under  a  geological  point  of  view     .     Page  230-258 


CHAPTER  YI. 

THE    DENUDATION    OF    THE    LAIHD— Continued, 

Denudation  aided  by  recently  ejected  castings  flowing 
down  inclined  grass-covered  surfaces — The  amount 
of  earth  which  annually  flows  downwards — -The 
effect  of  tropical  rain  on  worm  castings — The  finest 
particles  of  earth  washed  completely  away  from 
castings — The  disintegration  of  dried  castings  into 
]>ellets,  and  their  rolling  down  inclined  surfaces — 
The  formation  of  little  ledges  on  hill-sides,  in  part 
due  to  the  accumulation  of  disintegrated  castings — 
Castings  blown  to  leeward  over  level  land — An 
attempt  to  estimate  the  amount  thus  blown — The 
dogradation  of  ancient  encampments  and  tumuli — 
The  preservation  of  the  crowns  and  furrows  on  land 
anciently  p!oughed — The  formation  and  amount  of 
mould  over  the  Chalk  formation      .  .     259-304 


CONTENTS.  '«'" 

CHAPTER  YII. 

C025CLUSION. 

Summary  of  the  part  which  worms  havo  played  in  the 
history  of  the  world — Their  aid  in  the  disintegra- 
tion of  rocks — In  the  denudation  of  the  land — Iii 
the  preservation  of  ancient  remains — In  the  pre- 
paration of  the  soil  for  the  growth  of  plants — 
Mental  powers  of  worms — Conclusion      .     30«^-ol(i 


Index 315-326 


THE 


FORMATION  OF  VEGETABLE  MOULD, 

THROUGH  THE  ACTION  OF  WORMS,  WITH 
OBSERVATIONS  ON  THEIR  HABITS. 


INTRODUCTION. 

The  share  which  worms  have  taken  in  the 
formation  of  the  layer  of  vegetable  mould, 
which  covers  the  whole  surface  of  the  land 
in  every  moderately  humid  country,  is  the 
subject  of  the  present  volume.  This  mould 
is  generally  of  a  blackish  colour  and  a  few 
inches  in  thickness.  In  different  districts  it 
differs  but  little  in  appearance,  although  it 
may  rest  on  various  subsoils.  The  uniform 
fineness  of  the  particles  of  which  it  is  com- 
posed is  one  of  its  chief  characteristic  features ; 
and  this  may  be  well  observed  in  any  gravelly 
country,   where    a    recently-ploughed     field 


2  INTRODUCTION. 

immediately  adjoins  one  which  has  long  re- 
mained undisturbed  for  pasture,  and  where 
the  vegetable  mould  is  exposed  on  the  sides 
of  a  ditch  or  hole.  The  subject  may  appear 
an  insignificant  one,  but  we  shall  see  that 
it  possesses  some  interest  5  and  the  maxim 
"  de  minimis  lex  non  curat,"  does  not  apply 
to  science.  Even  Elie  de  Beaumont,  who 
generally  undervalues  small  agencies  and 
their  accumulated  effects,  remarks.*  "  la 
"  couche  tres-mince  de  la  terre  vegetale  est  un 
*'  monument  d'une  haute  antiquite,  et^  par  le 
''  fait  de  sa  permanence,  un  objet  digne  d'oc- 
''  cuper  le  geologue,  et  capable  de  lui  fournir 
''des  remarques  interessantes."  Although 
the  superficial  layer  of  vegetable  mould  as  a 
whole  no  doubt  is  of  the  highest  antiquity, 
yet  in  regard  to  its  permanence,  we  shall  here- 
after see  reason  to  b,elieve  that  its  component 
particles  are  in  most  cases  removed  at  not  a 
very  slow  rate,  and  are  replaced  by  others 
due  to  the  disintegration  of  the  underlying 
materials. 

As  I  was  led  to  keep  in  my  study  during 
many  months  worms  in  pots  filled  with  earthy 

*  '  Lecons  de  Geologie  Pratique,'  torn.  i.  1845,  p.  140 


INTEODUCTION.  3 

r  became  interested  in  them,  and  wished  to 
learn  how  far  they  acted  consciously,  and  how 
much  mental  power  they  displayed.  I  was 
the  more  desirous  to  learn  something  on  this 
head,  as  few  observations  of  this  kind  have 
been  made,  as  far  as  I  know,  on  animals  so 
low  in  the  scale  of  organization  and  so 
poorly  provided  with  sense-organs,  as  are 
earth-worms. 

In  the  year  1837,  a  short  paper  was  read 
by  me  before  the  Geological  Society  of 
London,*  "  On  the  Formation  of  Mould,"  in 
which  it  was  shown  that  small  fragments  of 
burnt  marl,  cinders,  Src,  which  had  been 
thickly  strewed  over  the  surface  of  several 
meadows,  were  found  after  a  few  years  lying 
at  the  depth  of  some  inches  beneath  the  turf, 
but  still  forming  a  layer.  This  apparent 
sinking  of  superficial  bodies  is  due,  as 
was  first  suggested  to  me  by  Mr.  Wedgwood 
of  Maer  Hall  in  Staffordshire,  to  the  large 
quantity  of  fine  earth  continually  brought 
up  to  the  surface  by  worms  in  the  form  ol 
castings.     These  castings  are  sooner  or  later 

*  '  Transactions  Geolog.  Soc'  vol.  v.  p.  505.      Read   Novem- 
ber 1.  1837. 


4  INTKODUCTION. 

spread  out  and  cover  up  any  object  left  on 
the  surface.  I  was  thus  led  to  conclude  that 
all  the  vegetable  mould  over  the  whole  coun* 
try  has  passed  many  times  through,  and  will 
again  pass  many  times  through,  the  intestinal 
canals  of  worms.  Hence  the  term  "animal 
mould "  would  be  in  some  respects  more 
appropriate  than  that  commonly  used  of 
*'  vegetable  mould." 

Ten  years  after  the  publication  of  my  paper, 
M.  D' Archiac,  evidently  influenced  by  the  doc* 
trines  of  Elie  de  Beaumont,  wrote  about  my 
"singuliere  theorie,"  and  objected  that  it  could 
apply  only  to  *'les  prairies  basses  et  humides;" 
and  that  "les  terres  labourees,  les  bois,  les 
prairies  elevees,  n'apportent  aucune  preuve 
a  Tappui  de  cette  maniere  de  voir."  *  But  M. 
D' Archiac  must  have  thus  argued  from  inner 
consciousness  and  not  from  observation,  for 
worms  abound  to  an  extraordinary  degree  in 
kitchen  gardens  where  the  soil  is  continually 
worked,  though  in  such  loose  soil  they  generally 
dejTosit  their  castings  in  any  open  cavities  or 
within  their  old  burrows  instead  of  on  the 
surface.     Yon  Hensen  estimates  that  there  are 

*  •  Histoire  des  progrfes  de  la  Geologic,'  torn.  i.  1847,  p.  224, 


INTRODUCTION.  5 

about  twice  as  many  worms  in  gardens  as  in 
corn-field^,.*  With  respect  to  '*  prairies 
elevees,"  I  do  not  know  how  it  may  be  in 
France,  but  nowhere  in  England  have  I  seen 
the  ground  so  thickly  covered  with  castings 
as  on  commons,  at  a  height  of  several  hundred 
feet  above  the  sea.  In  woods  again,  if  the  loose 
leaves  in  autumn  are  removed,  the  whole 
surface  will  be  found  strewed  with  castings. 
Dr.  King,  the  superintendent  of  the  Botanic 
Grarden  in  Calcutta,  to  whose  kindness  I  am 
indebted  for  many  observations  on  earth- 
worms, informs  me  that  he  found,  near  Nancy 
in  France,  the  bottom  of  the  State  forests 
covered  over  many  acres  with  a  spongy  layer, 
composed  of  dead  leaves  and  innumerable 
worm-castings.  He  there  heard  the  Professor 
of  "  Amenagement  des  Forets "  lecturing  to 
his  pupils,  and  pointing  out  this  case  as  a 
"  beautiful  example  of  the  natural  cultiva- 
''  tion  of  the  soil ;  for  year  after  year  the 
*'  thrown-up  castings  cover  the  dead  leaves ; 
*'  the  result  being  a  rich  humus  of  great 
*'  thickness.'* 

*  '  Zeitschrift  fiir  wissenschaft.   Zoologl;,*  B    xxviii.  1877 
p*  361. 


6  INTRODUCTION. 

In  tlie  year  1869,  Mr.  Fish*  rejected  my 
conclusions  with  respect  to  the  part  which 
worms  have  played  in  the  formation  of  veget- 
ahle  mould, merely  on  account  of  their  assumed 
incapacity  to  do  so  much  work.  He  remarks 
that  ''considering  their  weakness  and  their 
'  size,  the  work  they  are  represented  to 
"  have  accomplished  is  stupendous."  Here  wo 
have  an  instance  of  that  inability  to  sum 
up  the  effects  of  a  continually  recurrent 
cause,  which  has  often  retarded  the  progress 
of  science,  as  formerly  in  the  case  of  geology, 
and  more  recently  in  that  of  the  principle 
of  evolution. 

Although  these  several  objections  seemed 
to  me  to  have  no  weight,  yet  I  resolved  to 
make  more  observations  of  the  same  kind  as 
those  published,  and  to  attack  the  problem  on 
another  side ;  namely,  to  weigh  all  the  cast- 
ings thrown  up  within  a  given  time  in  a 
measured  space,  instead  of  ascertaining  the 
rate  at  which  objects  left  on  the  surface  were 
buried  by  worms.  But  some  of  my  observa- 
tions have  been  rendered  almost  superfluous 
by   an    admirable    paper    by   Yon   Hen  sen, 

*  '  Gardeners'  Chrouicle,'  April  17,  18G9,  p.  418. 


IKTRODUTIOIS^.  7 

already  alluded  to,  whicli  appeared  in  1877. 
Before  entering  on  details  with  respect  to  the 
castings,  it  will  be  advisable  to  give  some 
account  of  the  habits  of  worms  from  ray 
own  observations  and  from  those  of  other 
naturalists. 


HABITS  OF   WORMS.  Chap.  L 


CHAPTER  I. 

HABITS    OF   WORMS. 

Nature  of  the  sites  inhabited — Can  live  long  under  water — 
Nocturnal — Wander  about  at  night — Often  lie  close  to  the 
mouths  of  their  burrows,  and  are  thus  destroyed  in  large 
numbers  by  birds — Structure — Do  not  possess  eyes,  but  can 
distinguish  between  light  and  darkness — Retreat  rapidly  when 
brightly  illuminated,  not  by  a  reflex  action— Power  of  attention 
— Sensitive  to  heat  and  cold — Completely  deaf — Sensitive  to 
vibrations  and  to  touch — Feeble  povrer  of  smell — Taste — 
Mental  qualities — Nature  of  food — Omnivorous — Digestion — 
Leaves  before  being  swallowed,  moistened  with  a  fluid  of  the 
nature  of  the  pancreatic  secretion — Extra-stomachal  digestion 
— Calciferous  glands,  structure  of — Calcareous  concretions 
formed  in  the  anterior  pair  of  glands — The  calcareous  matter 
primarily  an  excretion,  but  secondarily  serves  to  neutralise  the 
acids  generated  during  the  digestive  process. 

Earth-worms  are  distributed  throughout  the 
world  under  the  form  of  a  few  genera,  which 
externally  are  closely  similar  to  one  another. 
The  British  species  of  Lumbricus  have  never 
been  carefully  monographed;  but  we  may 
judge  of  their  probable  number  from  those 
inhabiting  neighbouring  countries.  In  Scan- 
dinavia there  are  eight  species,  according  to 


Chap.  I.  SITES   INHABITED.  9 

Eisen  ;*  but  two  of  these  rarely  burrow  in  the 
ground,  and  one  inhabit?!  very  wet  places  oi 
even  lives  under  the  water.  We  are  here 
t^oncerned  only  with  the  kinds  which  bring 
up  earth  to  the  surface  in  tlie  form  of  cast- 
ings. Hoifmeister  says  that  the  species  in 
Germany  are  not  well  known,  but  gives  the 
same  number  as  Eisen,  together  with  some 
strongly  marked  varieties.! 

Earth-worms  abound  in  England  in  many 
different  stations.  Their  castings  may  be 
seen  in  extraordinary  numbers  on  commons 
and  chalk-downs,  so  as  almost  to  cover  the 
whole  surface,  wliere  the  soil  is  poor  and  the 
grass  short  and  thin.  But  they  are  almost  or 
quite  as  numerous  in  some  of  the  London 
parks,  where  the  grass  grows  well  and  the 
soil  appears  rich.  Even  on  the  same  field 
worms  are  much  more  frequent  in  some  places 
than  in  others,  without  any  visible  difference 
in  the  nature  of  the  soil.  They  abound  in 
paved  court-yards  close  to  houses  ;  and  an 
instance    will    be    given  in  which  they  had 

*  'Bidrag  till  Skandinaviens  01igoclia}tfauna,'  1871. 
t  *  Die  bis  jetzt  bekaunten  Arteu  aus  der  Familie  der  Eegeii* 
ftli  mer,'  184:5. 


10  HABITS  OF  WOKMS.  Chap.  L 

burrowed  through  the  floor  of  a  very  damp 
cellar.  I  have  seen  worms  in  black  peat  in  a 
boggy  field ;  but  they  are  extremely  rare,  or 
quite  absent  in  the  drier,  brown,  fibrous  peaf, 
which  is  so  much  valued  by  gardeners.  On 
dry,  sandy  or  gravelly  tracks,  where  heath 
with  some  gorse,  ferns,  coarse  grass,  moss  and 
lichens  alone  grow,  hardly  any  worms  can 
be  found.  But  in  many  parts  of  England, 
wherever  a  path  crosses  a  heath,  its  surface 
becomes  covered  with  a  fine  short  sw^ard. 
Whether  this  change  of  vegetation  is  due  to 
the  taller  plants  being  killed  by  the  occasional 
trampling  of  man  and  animals,  or  to  the  soil 
being  occasionally  manured  by  the  droppings 
from  animals,  I  do  not  know.*  On  such 
grassy  paths  worm-castings  may  often  be  seen. 
On  a  heath  in  Surrey,  which  was  carefully 
examined,  there  were  only  a  few  castings  on 
these  paths,  where  they  were  much  inclined  ; 

*  There  is  even  some  reason  to  believe  that  pressure  is  actually 
favourable  to  the  growth  of  grasses,  for  Professor  Buckman,  who 
made  many  observations  on  their  growth  in  the  experimental 
gardens  of  the  Eoyal  Agricultural  College,  remarks  ('  Gardeners' 
Chronicle,'  1854,  p.  619) :  "  Another  circumstance  in  the  cultiva- 
tion of  grasses  in  the  separate  form  or  small  patches,  is  the 
impossibility  of  rolling  or  treading  them  firmly,  vvithout  whioli 
uo  pasture  can  continue  good." 


Chap.  I.  SITES   INHABITED.  II 

but  on  the  more  level  parts,  where  a  bed  of 
fine  earth  had  been  washed  down  from  the 
steeper  parts  and  had  accumulated  to  a  thick- 
ness cfafew  inches,  worm-castings  abounded. 
These  spots  seemed  to  be  overstocked  with 
worms,  so  that  they  had  been  compelled  to 
spread'  to  a  distance  of  a  few  feet  from  the 
grassy  paths,  and  here  their  castings  had  been 
thrown  up  among  the  heath ;  but  beyond  this 
limit,  not  a  single  casting  could  be  found.  A 
layer,  though  a  thin  one,  of  fine  earth,  which 
probably  long  retains  some  moisture,  is  in 
all  cases,  as  I  believe,  necessary  for  their 
existence ;  and  the  mere  compression  of  the 
soil  appears  to  be  in  some  degree  favourable 
to  them,  for  they  often  abound  in  old  gravel 
walks,  and  in  foot-paths  across  fields. 

Beneath  large  trees  few  castings  can  be 
found  during  certain  seasons  of  the  year,  and 
this  is  apparently  due  to  the  moisture  having 
been  sucked  out  of  the  ground  by  the  innu- 
merable roots  of  the  trees ;  for  such  places 
may  be  seen  covered  with  castings  after  the 
heavy  autumnal  rains.  Although  most  cop- 
pices and  woods  support  many  worms,  yet  in  a 
forest  of  tall  and  ancient  beech-trees  in  Knole 


12  HABITS   OF   WORMS.  Chap.  I. 

Park,  where  the  ground  beneath  was  bare  of 
all  vegetation,  not  a  single  casting  could  be 
fDund  over  wide  spaces,  even  during  the 
autumn.  Nevertheless,  castings  were  abun- 
dant on  some  grass-covered  glades  and  in- 
dentations which  penetrated  this  forest.  On 
the  mountains  of  North  Wales  and  on  the 
Alps,  worms,  as  I  have  been  informed,  are  in 
most  places  rare  ;  and  this  may  perhaps  be 
due  to  the  close  proximity  of  the  sub- 
jacent rocks,  into  which  worms  cannot 
burrow  during  the  winter  so  as  to  escape 
being  frozen.  Dr.  Mcintosh,  however,  found 
worm-castings  at  a  height  of  1500  feet  on 
Schiehallion  in  Scotland.  They  are  numerous 
on  some  hills  near  Turin  at  from.  2000  to 
3000  feet  above  the  sea,  and  at  a  great 
altitude  on  the  Nilgiri  Mountains  in  South 
India  and  on  the  Himalaya. 

Earth-worms  must  be  considered  as  terres- 
trial animals,  though  they  are  still  in  one 
sense  semi-aquatic,  like  the  other  members  of 
the  great  class  of  annelids  to  which  they 
belong.  M.  Perrier  found  that  their  ex- 
posure to  the  dry  air  of  a  room  for  only  a 
single    night    was    fatal   to    them.     On    the 


Ohap.  I.  NOCTUENAL.  13 

other  hand  he  kept  several  large  worms  alive 
for  nearly  four  months,  completely  submerged 
in  water.*  During  the  summer  when  the 
ground  is  dry,  they  penetrate  to  a  consider- 
able depth  and  cease  to  work,  as  they  do 
during  the  winter  when  the  ground  is  frozen. 
Worms  are  nocturnal  in  their  habits,  and  at 
night  may  be  seen  crawling  about  in  large 
numbers,  but  usually  with  their  tails  still 
inserted  in  their  burrows.  By  the  expansion 
of  this  part  of  their  bodies,  and  with  the  help 
of  the  short,  slightly  reflexed  bristles,  with 
which  their  bodies  are  armed,  they  hold 
so  fast  that  they  can  seldom  be  dragged 
out  of  the  ground  without  being  torn  into 
pieces.f  During  the  day  they  remain  in 
their  burrows,  except  at  the  pairing  season, 
when  those  which  inhabit  adjoining  burrows 
expose  the  greater  part  of  their  bodies  for 
an  hour  or  two  in  the  early  morning.     Sick 


*  I  shall  have  occasion  often  to  refer  to  M.  Perricr's  admirable 
memoir,  'Organisation  des  Lombriciens  terrestres'  in  'Archives 
de  Zoolcg.  exper.'  torn.  iii.  1874,  p.  372.  0.  F.  Morren  ('  De 
Lumbrici  terrestris,'  1829,  p.  14)  fouud  that  worms  endured 
immersion  for  fifteen  to  twenty  days  in  summer,  but  that  ia 
vi'inter  they  died  when  thus  treated. 

t  Morren,  'De  Lumbrici  terrestris,'  &c.,  1829,  p.  67. 


14  HABITS   OF   WORMS.  CnAr.  1. 

individuals,  which  are  generally  affected  by 
the  parasitic  larvae  of  a  fly,  must  also  be  ex- 
cepted, as  they  wander  about  during  the  day 
and  die  on  the  surface.  After  heavy  rain 
succeeding  dry  weather,  an  astonishing  num- 
ber of  dead  worms  may  sometimes  be  seen 
lying  on  the  ground.  Mr.  Galton  informs 
me  that  on  one  such  occasion  (March,  1881), 
the  dead  worms  averaged  one  for  every 
two  and  a  half  paces  in  length  on  a  walk  in 
Hyde  Park,  four  paces  in  width.  He  counted 
jio  less  than  45  dead  worms  in  one  place  in 
a  length  of  sixteen  paces.  From  the  facts 
above  given,  it  is  not  probable  that  these 
worms  could  have  been  drowned,  and  if  they 
had  been  drowned  they  would  have  perished 
in  their  burrows.  I  believe  that  they  were 
already  sick,  and  that  their  deaths  were 
merely  hastened  by  the  ground  being  flooded. 
It  has  often  been  said  that  under  ordinary 
circumstances  healthy  worms  never,  or  very 
rarely,  completely  leave  their  burrows  at 
night ;  but  this  is  an  error,  as  White  of  Sel- 
borne  long  ago  knew.  In  the  morning,  aftei 
there  has  been  heavy  rain,  the  film  of  mud 
or  of  very  fine  sand  over  gravel-w^alks  is  often 


Chap.  I.    WANDEK  FKOM   THEIR  BUEROWS.  15 

plainly  marked  witli  their  tracks.  I  have 
ijoticed  this  from  August  to  May,  both  months 
included,  and  it  probably  occurs  during  the 
two  remaining  months  of  the  year  when 
they  are  wet.  On  these  occasions,  very  few 
dead  worms  could  anywhere  be  seen.  On 
January  31,  1881,  after  a  long-continued 
and  unusually  severe  frost  with  much  snow, 
as  soon  as  a  thaw  set  in,  the  walks  were 
marked  with  innumerable  tracks.  On  one 
occasion,  five  tracks  were  counted  crossing 
a  space  of  only  an  inch  square.  They  could 
sometimes  be  traced  either  to  or  from  the 
mouths  of  the  burrows  in  the  gravel-walks, 
for  distances  between  2  or  3  up  to  15  yards. 
I  have  never  seen  two  tracks  leading  to  the 
same  burrow ;  nor  is  it  likely,  from  what  we 
shall  presently  see  of  their  sense-organs,  that 
a  worm  could  find  its  way  back  to  its  burrow 
after  having  once  left  it.  They  apparently 
leave  their  burrows  on  a  voyage  of  discovery, 
and  thus  they  find  new  sites  to  inhabit. 

Morren  states  *  that  worms  often  lie  for 
hours  almost  motionless  close  beneath  the 
mouths  of  their  burrows.  I  have  occasionally 
Qoticed   the    same   fact  with  worms  kept  in 

*  '  Do  Liimbrici  terrestris,'  &c.,  p.  14. 


16  HABITS   OF   WORMS.  Chap.  1 

pots  in  the  house ;  so  that  by  looking  down 
into  their  burrows,  their  heads  could  just  be 
seen.  If  the  ejected  earth  or  rubbish  over 
the  barrows  be  suddenly  removed,  the  end 
of  the  worm's  body  may  very  often  be  seen 
rapidly  retreating.  This  habit  of  lying  near 
the  surface  leads  to  their  destruction  to  an 
immense  extent.  Every  morning  during  cer- 
tain seasons  of  the  year,  the  thrushes  and 
blackbirds  on  all  the  lawns  throughout  the 
country  draw  out  of  their  holes  an  astonishing 
number  of  worms ;  and  this  they  could  not 
do,  unless  they  lay  close  to  the  surface.  It 
is  not  probable  that  worms  behave  in  this 
manner  for  the  sake  of  breathing  fresh  air, 
for  we  have  seen  that  they  can  live  for  a 
long  time  under  water.  I  believe  that  they  lie 
near  the  surface  for  the  sake  of  warmth,  es- 
pecially in  the  morning ;  and  we  shall  here- 
after find  that  they  often  coat  the  mouths 
of  their  burrows  with  leaves,  apparently  to 
prevent  their  bodies  from  coming  into  close 
contact  with  the  cold  damp  earth.  It  is  said 
that  they  completely  close  their  burrows 
during  the  winter. 

Structure, — A  few  remarks  must  be  made 
on  this  subject.     The  body  of  a  large  worm 


Chap.  J.  THEIR   STRUCTURE.  17 

consists  of  from  100  to  200  almost  cylindrical 
rings  or  segments,  each  furnished  with  minute 
bristles.  The  muscular  system  is  well 
developed.  Worms  can  crawl  backwards  as 
well  as  forwards,  and  by  the  aid  of  their 
affixed  tails  can  retreat  with  extraordinary 
rapidity  into  their  burrows.  The  mouth  is 
situated  at  the  anterior  end  of  tlie  body,  and 
is  provided  with  a  little  projection  (lobe  or  lip, 
as  it  has  been  variously  called)  which  is  used 
for  prehension.  Internally,  behind  the  mouth, 
there  is  a  strong  pharynx,  shown  in  the  ac- 
companying diagram  (Fig.  1)  which  is  pushed 
forwards  when  the  animal  eats,  and  this  part 
corresponds,  according  to  Perrier,  with  the  pro- 
trudable  trunk  or  proboscis  of  other  annelids. 
The  pharynx  leads  into  the  oesophagus,  on 
each  side  of  which  in  the  lower  part  there 
are  three  pairs  of  large  glands,  which  secrete 
a  surprising  amount  of  carbonate  of  lime. 
These  calciferous  glands  are  highly  remark- 
able, for  nothing  like  them  is  known  in  any 
other  animal.  Their  use  will  be  discussed 
when  we  treat  of  the  digestive  process.  In 
most  cf  the  species,  the  oesophagus  is  enlarged 
into   a    crop  in  front  of   the  gizzard.      This 


18 


HABITS   OF   WORMS. 


Chap.  L 


latter 


organ   is 


Mout'i. 


Pharynx. 


(Esophagus. 


Calciferous  glands. 


Esophagus. 


Crop. 


Gizzaid. 


1^^      Upper  part  of 
testin.\ 


Fig  .  1. 

Diagram  of  the  alimen- 
tary canal  of  an  earth- 
worm (Lumhricus), 
copied  from  Ray  Lan- 
kester  in  '  Quart. 
Journ.  of  Microscop. 
Soc'  vol.  XV.  N.S. 
pi.  vii. 


lined  with  a  smooth  thick 
chitinous  membrane,  and 
is  surrounded  by  weak 
longitudinal,  but  by  power- 
ful transverse  muscles. 
Perrier  saw  these  muscles 
in  energetic  action;  and,  as 
he  remarks,  the  trituration 
of  the  food  must  be  chiefly 
eflected  by  this  organ,  for 
worms  possess  no  jaws  or 
teeth  of  any  kind.  Grains 
of  sand  and  small  stones, 
from  the  2V  ^^  ^  little 
more  than  the  ^^  inch  in 
diameter,  may  generally 
be  found  in  their  gizzards 
and  intestines.  As  it  is 
certain  that  worms  swal- 
low many  little  stones,  in- 
dependently of  those  swal- 
lowed while  excavating 
their  burrows,  it  is  prob- 
able that  they  serve,  like 
mill-stones,  to  triturate 
their  food.  The  gizzard 
opens    into    tlie   intestine, 


Chap.  I.  THEIR  SENSES.  19 

which  runs  in  a  straight  course  to  the  vent 
at  the  posterior  end  of  the  body.  The  intes- 
tine presents  a  remarkable  structure,  the 
typhosohs,  or,  as  the  old  anatomists  called  it, 
an  intestine  within  an  intestine  ;  and  Clapa- 
rede*  has  shown  that  this  consists  of  a 
deep  longitudinal  involution  of  the  walls  of 
the  intestine,  by  which  means  an  extensive 
absorbent  surface  is  gained. 

The  circulatory  system  is  well  developed. 
Worms  breathe  by  their  skin,  as  they  do  not 
possess  any  special  respiratory  organs.  The 
two  sexes  are  united  in  the  same  individual,  but 
two  individuals  pair  together.  The  nervous 
system  is  fairly  well  developed  ;  and  the  two 
almost  confluent  cerebral  ganglia  are  situated 
very  near  to  the  anterior  end  of  the  body. 

Senses, — Worms  are  destitute  of  eyes,  and 
at  first  I  thought  that  they  wxre  quite  in- 
sensible to  light ;  for  those  kept  in  confine- 
ment were  repeatedly  observed  by  the  aid  of 
a  candle,  and  others  out  of  doors  by  the  aid 
of  a  lantern,  yet  they  were  rarely  alarmed, 
although   extremely   timid   animals.      Other 

*  Histolog.  Untersucliungeii  iiber  die  Eegenwiirmer.     *Zcit- 
schrift  fiir  wissenschaft.  Zoologie/  B.  xix.,  1869,  p.  611. 


20  HABITS  OF  WORMS.  Cuap.  L 

persons  have  found  no  difficuity  in  observing 
worms  at  niglit  by  the  same  means.* 

Hoffmeister,  however,  states  f  that  worms, 
with  the  exception  of  a  few  individuals,  are 
extremely  sensitive  to  light ;  but  he  admits 
that  in  most  cases  a  certain  time  is  requisite 
for  its  action.  These  statements  led  me  to 
watch  on  many  successive  nights  worms  kept 
in  pots,  which  were  protected  from  currents 
of  air  by  means  of  glass  plates.  The  pots 
were  approached  very  gently,  in  order  that 
no  vibration  of  the  floor  should  be  caused. 
When  under  these  circumstances  worms  were 
illuminated  by.  a  bull's-eye  lantern  having 
slides  of  dark  red  and  blue  glass,  which  in- 
tercepted so  much  light  that  they  could  be  seen 
only  with  some  difficulty,  they  were  not  at  all 
affected  by  this  amount  of  light,  however  long 
they  were  exposed  to  it.  The  light,  as  far 
as  I  could  judge,  was  brighter  than  that  from 
the  full  moon.  Its  colour  apparently  made 
ao  difference  in  the  result.     When  they  were 


*  For  instance,  Mr.  Bridgman  and  Mr.  Newman  ('  The 
Zoologist/ vol.  vii.  1849,  p.  2576),  and  some  friends  who  observtvi 
worms  for  me. 

t  '  Familie  der  Regenwiirmer,'  1845,  p.  18. 


Chap.  I.  THEIR   SENSES.  2i 

illuminated  by  a  candle,  or  even  by  a  bright 
paraffin  lamp,  tbey  were  not  usually  affected 
at  first.  Nor  were  they  when  the  light  was 
alternately  admitted  and  shut  off.  Some- 
times, however,  they  behaved  very  differ- 
ently, for  as  soon  as  the  light  fell  on  them, 
they  withdrew  into  their  burrows  with 
almost  instantaneous  rapidity.  This  occurred 
perhaps  once  out  of  a  dozen  times.  When 
they  did  not  withdraw  instantly,  they  often 
raised  the  anterior  tapering  ends  of  their 
bodies  from  the  ground,  as  if  their  attention 
was  aroused  or  as  if  surprise  was  felt ;  or 
they  moved  their  bodies  from  side  to  side  as 
if  feeling  for  some  object.  They  appeared 
distressed  by  the  light ;  but  I  doubt  whether 
this  was  really  the  case,  for  on  two  occasions 
after  withdrawing  slowly,  they  remained  for 
a  long  time  with  their  anterior  extremities 
protruding  a  little  from  the  mouths  of  their 
burrows,  in  which  position  they  were  readv 
for  instant  and  complete  withdrawal. 

When  the  light  from  a  candle  was  con- 
centrated by  means  of  a  large  lens  on  the 
anterior  extremity,  they  generally  withdrew 
instantly  ;  but  this  concentrated  light  failed 


22  HABITS   OF   WORMS.  Chap.  1 

to  act  perhaps  once  out  of  half  a  dozen  trials. 
The  light  was  on  one  occasion  concentrated 
on  a  worm  lying  beneath  water  in  a  saucer^ 
and  it  instantly  withdrew  into  its  burrow. 
In  all  cases  the  duration  of  the  light,  unless 
extremely  feeble,  made  a  great  difference  in 
the  result ;  for  worms  left  exposed  before  a 
paraffin  lamp  or  a  candle  invariably  retreated 
into  their  burrows  within  from  five  to  fifteen 
minutes ;  and  if  in  the  evening  the  pots  were 
illuminated  before  the  worms  had  come  out  of 
their  burrows,  they  failed  to  appear. 

From  the  foregoing  facts  it  is  evident  that 
light  affects  worms  by  its  intensity  and  by 
its  duration.  It  is  only  the  anterior 
extremity  of  the  body,  where  the  cerebral 
ganglia  lie,  which  is  affected  by  light,  as 
Hoffmeister  asserts,  and  as  I  observed  on 
many  occasions.  If  this  part  is  shaded,  other 
parts  of  the  body  may  be  fully  illuminated, 
and  no  effect  will  be  produced.  As  these 
animals  have  no  eyes,  we  must  suppose  that 
the  light  passes  through  their  skins,  and  in 
some  manner  excites  their  cerebral  ganglia. 
It  appeared  at  first  probable  that  the  dif- 
ferent manner  in  which  they  were  affected  on 


Chap.  L  THEIE   SENSES.  23 

different  occasions  miglit  be  explained,  either 
by  the  degree  of  extension  of  their  skin  and 
its  consequent  transparency,  or  by  some 
particular  incidence  of  the  liglit ;  but  I 
could  discover  no  such  relation.  One  thing 
was  manifest,  namely  that  when  worms  were 
employed  in  dragging  leaves  into  their 
burrows  or  in  eating  them,  and  even  during 
the  short  intervals  whilst  they  rested  from 
their  work,  they  either  did  not  perceive 
the  light  or  were  regardless  of  it ;  and  this 
occurred  even  when  the  light  was  concentrated 
on  them  through  a  large  lens.  So,  again, 
whilst  they  are  paired,  they  will  remain  for 
an  hour  or  two  out  of  their  burrows,  fully 
exposed  to  the  morning  light ;  but  it  appears 
from  what  Hoffmeister  says  that  a  light 
will  occasionally  cause  paired  individuals  to 
separate. 

When  a  worm  is  suddenly  illuminated  and 
dashes  like  a  rabbit  into  its  burrow — to  use 
the  expression  employed  by  a  friend — we  are 
at  first  led  to  look  at  the  action  as  a  reflex  one. 
The  irritation  of  the  cerebral  ganglia  appears 
to  cause  certain  muscles  to  contract  in  an 
inevitable  mann^^r,  independently  of  the  will 

3 


24  HABITS  OF   WORMS.  Chap.  I 

or  consciousness  of  the  animal,  as  if  it  were 
an  automaton.  But  the  different  effect 
which  a  h'ght  produced  on  different  occasions; 
and  especially  the  fact  that  a  worm  when  in 
any  way  employed  and  in  the  intervals  ol 
such  employment,  whatever  set  of  muscles 
and  ganglia  may  then  have  been  brought  into 
j)lay,  is  often  regardless  of  light,  are  opposed 
to  the  view  of  the  sudden  withdrawal  being 
a  simple  reflex  action.  With  the  higher 
animals,  when  close  attention  to  some  object 
leads  to  the  disregard  of  the  impressions 
which  other  objects  must  be  producing  on 
them,  we  attribute  this  to  their  attention 
being  then  absorbed  ;  and  attention  implies 
the  presence  of  a  mind.  Every  sportsman 
knows  that  he  can  approach  animals  whilst 
they  are  grazing,  fighting  or  courting,  much 
more  easily  than  at  other  times.  The  state, 
also,  of  the  nervous  system  of  the  higher 
animals  differs  much  at  different  times,  for 
instance,  a  horse  is  much  more  readily  startled 
at  one  time  than  at  another.  The  comparison 
here  implied  between  the  actions  of  one  oJ 
the  higher  animals  and  of  one  so  low  in  the 
scale    as    an    earth-w^orm,    may    appear    far- 


Chap.  I.  THEIR   SENSES.  25 

fetched ;  for  we  tlms  attribute  to  the  worm 
attention  and  some  mental  power,  neverthe- 
less I  can  see  no  reason  to  doubt  the  justice 
of  the  comparison. 

Although  worms  cannot  be  said  to  possess 
the  power  of  vision,  their  sensitiveness  to 
light  enables  them  to  distinguish  between 
day  and  night ;  and  they  thus  escape  extreme 
danger  from  the  many  diurnal  animals  which 
prey  on  them.  Their  withdrawal  into  their 
burrows  during  the  day  appears,  however, 
to  have  become  an  habitual  action ;  for 
worms  kept  in  pots  covered  by  glass-plates, 
over  which  sheets  of  black  paper  were 
spread,  and  placed  before  a  north-east  win- 
dow, remained  during  the  day-time  in  their 
burrows  and  came  out  every  night ;  and  they 
continued  thus  to  act  for  a  week.  No  doubt 
a  little  light  may  have  entered  between  the 
sheets  of  glass  and  the  blackened  paper ; 
but  we  know  from  the  trials  with  coloured 
glass,  that  worms  are  indifferent  to  a  small 
amount  of  light. 

Worms  appear  to  be  less  sensitive  to 
moderate  radiant  heat  than  to  a  bright  light. 
I  judge  of  this  from  having  held  at  diflferent 


26  HABITS  OF  WORMS.  CiiAP.  L 

times  a  poker  heated  to  dull  redness  near 
some  worms,  at  a  distance  which  caused  a 
very  sensible  degree  of  warmth  in  my  hand* 
One  of  them  took  no  notice ;  a  second  with- 
drew into  its  burrow,  but  not  quickly;  the 
third  and  fourth  much  more  quickly,  and  the 
fifth  as  quickly  as  possible.  The  light  from 
a  candle,  concentrated  by  a  lens  and  passing 
through  a  sheet  of  glass  which  would  intercept 
most  of  the  heat-rays,  generally  caused  a 
much  more  rapid  retreat  than  did  the  heated 
poker.  Worms  are  sensitive  to  a  low  temper- 
ature, as  may  be  inferred  from  their  not 
coming  out  of  their  burrows  during  a  frost. 

Worms  do  not  possess  any  sense  of  hearing. 
They  took  not  the  least  notice  of  the  shrill 
notes  from  a  metal  whistle,  which  was  re- 
peatedly sounded  near  them  ;  nor  did  they 
of  the  deepest  and  loudest  tones  of  a  bassoon. 
They  were  indifferent  to  shouts,  if  care  was 
taken  that  the  breath  did  not  strike  them. 
When  placed  on  a  table  close  to  the  keys  oi 
a  piano,  which  was  played  as  loudly  as 
possible^  they  remained  perfectly  quiet. 

Although  they  are  indifferent  to  undula- 
tions   in    the    air    audible   by   us,    they    are 


Chap.  I.  THEIR   SENSES.  27 

extremely  sensitive  to  vibrations  in  any  solid 
object.  When  the  pots  containing  two 
worms  which  had  remained  quite  indifferent 
to  the  sound  of  the  piano,  were  placed  on 
this  instrument,  and  the  note  C  in  the  bass 
clef  was  struck,  both  instantly  retreated  into 
their  burrows.  After  a  time  they  emerged, 
and  when  Gr  above  the  line  in  the  treble  clef 
was  struck  they  again  retreated.  Under 
similar  circumstances  on  another  night  one 
worm  dashed  into  its  burrow  on  a  very  high 
note  being  struck  only  once,  and  the  other 
worm  when  C  in  the  treble  clef  was  struck. 
On  these  occasions  the  worms  were  not 
touching  the  sides  of  the  pots,  which  stood 
in  saucers ;  so  that  the  vibrations,  before 
reaching  their  bodies,  had  to  pass  from  the 
sounding  board  of  the  piano,  through  the 
saucer,  the  bottom  of  the  pot  and  the  damp, 
not  very  compact  earth  on  which  they  lay 
with  their  tails  in  their  burrov/s.  They 
often  showed  their  sensitiveness  when  the 
pot  in  which  they  lived,  or  the  table  on 
which  the  pot  stood,  was  accidentally  and 
lightly  struck ;  but  they  appeared  less  sensi- 
tive to  such  jars  than  to  the  vibrations  of  the 


28  HABITS   OF   WORMS.  Chap.  F. 

piano ;  and  their  sensitiveness  to  jars  varied 
mnch  at  different  times.  It  has  often  been 
said  that  if  the  ground  is  beaten  or  otherwise 
made  to  tremble,  worms  believe  that  they 
are  pursued  by  a  mole  and  leave  their 
burrows.  I  beat  the  ground  in  many  places 
where  worms  abounded,  but  not  one  emerged. 
When,  however,  the  ground  is  dug  with  a 
fork  and  is  violently  disturbed  beneath  a 
worm,  it  will  often  crawl  quickly  out  of  its 
burrow. 

The  whole  body  of  a  worm  is  sensitive  to 
contact.  A  slight  puff  of  air  from  the  mouth 
causes  an  instant  retreat.  The  glass  plates 
placed  over  the  pots  did  not  fit  closely,  and 
blowing  through  the  Yery  narrow  chinks  thus 
left,  often  sufficed  to  cause  a  rapid  retreat. 
They  sometimes  perceived  tlie  eddies  in  the 
air  caused  by  cpickly  removing  the  glass 
plates.  When  a  worm  first  comes  out  of  its 
burrow,  it  generally  moves  the  much  ex- 
tended anterior  extremity  of  its  body  from 
side  to  side  in  all  directions,  apparently  as  an 
organ  of  touch ;  and  there  is  some  reason  to 
believe,  as  we  shall  see  in  the  next  chapter, 
that  they  are  thus  enabled  to  gain  a  general 


Chap.  I.  THEIR   SENSES.  29 

notion  of  the  form  of  an  object.  Of  all  tlieir 
senses  that  of  touch,  including  in  this  term 
the  perception  of  a  vibration,  seems  much  the 
most  highly  developed. 

In  worms  the  sense  of  smell  apparently  is 
confined  to  the  perception  of  certain  odours, 
and  is  feeble.  They  were  quite  indifferent  to 
my  breath,  as  long  as  I  breathed  on  them  very 
gently.  This  was  tried,  because  it  appeared 
possible  that  they  might  thus  be  warned  of 
the  approach  of  an  enemy.  They  exhibited 
the  same  indifference  to  my  breath  whilst  I 
chewed  some  tobacco,  and  while  a  pellet  of 
cotton-wool  with  a  few  drops  of  mille-fleurs 
perfume  or  of  acetic  acid  was  kept  in  my 
mouth.  Pellets  of  cotton-wool  soaked  in 
tobacco  juice,  and  in  millefleurs  perfume,  and 
in  paraffin,  were  held  with  pincers  and  were 
waved  about  within  two  or  three  inches  of 
several  worms,  but  they  took  no  notice.  On 
one  or  two  occasions,  however^  when  acetic 
acid  had  been  placed  on  the  pellets,  the  worms 
appeared  a  little  uneasy,  and  this  was 
probably  due  to  the  irritation  of  their  skins. 
The  perception  of  such  unnatural  odours 
would  be  of  no  service  to  worms ;  and  as  such 


30  HABITS  OF  WORMS.  Chap.  L 

timid  creatures  would  almost  certainly  exhibit 
some  signs  of  any  new  impression,  we  may 
conclude  that  they  did  not  perceive  these 
odours. 

The  result  was  different  when  cabbage- 
leaves  and  pieces  of  onion  were  employed, 
both  of  which  are  devoured  with  much  relish 
by  worms.  Small  square  pieces  of  fresh  and 
half-decayed  cabbage-leaves  and  of  onion 
bulbs  were  on  nine  occasions  buried  in  my 
pots,  beneath  about  i  of  an  inch  of  common 
garden  soil ;  and  they  were  always  discovered 
by  the  worms.  One  bit  of  cabbage  was  dis- 
covered and  removed  in  the  course  of  two 
hours ;  three  were  removed  by  the  next 
morning,  that  is,  after  a  single  night ;  tv*^o 
others  after  two  nights ;  and  the  seventh  bit 
after  three  nights.  Two  pieces  of  onion  were 
discovered  and  removed  after  three  nights. 
Bits  of  fresh  raw  meat,  of  which  worms  are 
very  fond,  were  buried,  and  were  not  dis- 
covered within  forty-eight  hours,  during 
which  time  they  had  not  become  putrid.  The 
earth  above  the  various  buried  objects  was 
generally  pressed  down  only  slightly,  so  as 
not   to   prevent   the  emission  of  any  odour. 


Chjip.  I.  THEIR   SENSES.  31 

On  two  occasions,  however,  the  surface  was 
well  watered,  and  was  thus  rendered  some- 
what compact.  After  the  bits  of  cabbage  and 
onion  had  been  remcved,  I  looked  beneath 
them  to  see  whether  the  worms  had  acci- 
dentally come  up  from  below,  but  there  was 
no  sign  of  a  burrow;  and  twice  the  buried 
objects  were  laid  on  pieces  of  tin-foil  which 
were  not  in  the  least  displaced.  It  is  of 
course  possible  that  the  worms  whilst  moving 
about  on  the  surface  of  the  ground,  with  their 
tails  affixed  within  their  burrows,  may  have 
poked  their  heads  into  the  places  where  the 
above  objects  were  buried  ;  but  I  have  never 
seen  worms  acting  in  this  manner.  Some 
pieces  of  cabbage-leaf  and  of  onion  were  twice 
buried  beneath  very  fine  ferruginous  sand, 
which  was  slightly  pressed  down  and  well 
watered,  so  as  to  be  rendered  very  compact, 
and  these  pieces  were  never  discovered.  On 
a  third  occasion  the  same  kind  of  sand  was 
neither  pressed  down  nor  watered,  and  the 
pieces  of  cabbage  were  discovered  and  re- 
moved after  the  second  night.  These  several 
facts  indicate  that  worms  possess  some  power 
of   smell ;    and   that   they   discover  by    thia 


32  HABITS   OF   WORMS.  Chap.  L 

means   odoriferous   and   mucli-coveted    kinds 
of  food. 

It  may  be  presumed  that  all  animals  which 
feed  on  various  substances  possess  the  sense 
of  taste,  and  this  is  certainly  the  case  with 
worms.  Cabbage-leaves  are  much  liked  by 
worms ;  and  it  appears  that  they  can  dis- 
tinguish between  different  varieties  ;  but  this 
may  perhaps  be  owing  to  differences  in  their 
texture.  On  eleven  occasions  pieces  of  the 
fresh  leaves  of  a  common  green  variety  and 
of  the  red  variety  used  for  pickling  w^ere 
given  them,  and  they  preferred  the  green, 
the  red  being  either  wholly  neglected  or  much 
less  gnawed.  On  two  other  occasions,  how 
ever,  they  seemed  to  prefer  the  red.  Half- 
decayed  leaves  of  the  red  variety  and  fresh 
leaves  of  the  green  were  attacked  about 
equally.  When  leaves  of  the  cabbage,  horse- 
radish (a  favourite  food)  and  of  the  onion  were 
given  together,  the  latter  were  always  and 
manifestly  preferred.  Leaves  of  the  cabbage, 
lime-tree,  Ampelopis,  parsnip  (Pastinaca),  and 
celery  (Apium)  were  likewise  given  together; 
and  those  of  the  celery  were  first  eaten.  But 
when  leaves  of  cabbage,  turnip^  beet,  celery, 


Chap.  I.  THEIR   SENSES.  33 

wild  cherry  and  carrots  were  given  together, 
the  two  latter  kinds,  especially  those  of  the 
carrot,  were  preferred  to  all  the  others, 
including  those  of  celery.  It  was  also  mani- 
fest after  many  trials  that  wild  cherry  leaves 
were  greatly  preferred  to  those  of  the  lime- 
tree  and  hazel  (Corylus).  According  to  Mr. 
Bridgman  the  half-decayed  leaves  of  Phlox 
verna  are  particularly  liked  by  worms.* 

Pieces  of  the  leaves  of  cabbage,  turnip, 
horse-radish  and  onion  were  left  on  the  pots 
during  22  days,  and  were  all  attacked  and 
had  to  be  renewed ;  •  but  during  the  w^hole 
of  this  time  leaves  of  an  Artemisia  and  of 
the  culinary  sage,  thyme  and  mint,  mingled 
with  the  above  leaves,  were  quite  neglected 
excepting  those  of  the  mint,  which  were  occa- 
sionally and  very  slightly  nibbled.  These 
latter  four  kinds  of  leaves  do  not  differ  in 
texture  in  a  manner  which  could  make  them 
disagreeable  to  worms  ;  they  all  have  a  strong 
taste,  but  so  have  the  four  first  mentioned 
kinds  of  leaves ;  and  the  wide  difference  in 
the  result  must  be  attributed  to  a  preference 
m  the  worms  for  one  taste  over  another. 

The  Zoologist;  vol.  vii,  184D,  p.  2576. 


34  HABITS   OF   WOE^IS.  Chzlp.  I, 

Mental  Qualities. — There  is  little  to  be  said 
on  this  head.  We  bav^e  seen  tbat  worms  are 
timid.  It  may  be  doubted  whether  they 
suffer  as  much  pain  when  injured,  as  they 
seem  to  express  by  their  contortions.  Judging 
by  their  eagerness  for  certain  kinds  of  food, 
they  must  enjoy  the  pleasure  of  eating. 
Their  sexual  passion  is  strong  enough  to 
overcome  for  a  time  their  dread  of  light. 
They  perhaps  have  a  trace  of  social  feeling, 
for  they  are  not  disturbed  by  crawling  over 
each  other's  bodies,  and  they  sometimes  lie 
in  contact.  According  to  Hoffmeister  they 
pass  the  winter  either  singly  or  rolled  up 
with  others  into  a  ball  at  the  bottom  of  their 
burrows.*  Although  worms  are  so  remark- 
ably deficient  in  the  several  sense-organs, 
this  does  not  necessarily  preclude  intelligence, 
as  we  know  from  such  cases  as  those  of  Laura 
Bridgman;  and  we  have  seen  that  when  theii 
attention  is  engaged,  they  neglect  impressions 
to  which  they  would  otherwise  have  attended ; 
and  attention  indicates  the  presence  of  a  mind 
of  some  kind.  They  are  also  much  more 
easily  excited  at  certain  times  than  at  others. 

*  '  Familie  rir.r  Regenwiirmcr,'  p.  13. 


Chap.  I.  MENTAL   QUALITIES.  35 

They  perform  a  few  actions  instinctively,  that 
is,  all  the  individuals,  including  the  young, 
perform  such  actions  in  nearly  the  same 
i'ashion.  This  is  shown  by  the  manner  in 
which  the  species  of  Perichseta  eject  their 
castings,  so  as  to  construct  towers;  also  by 
the  manner  in  which  the  burrows  of  the 
common  earth-worm  are  smoothly  lined  with 
fine  earth  and  often  with  little  stones,  and 
the  mouths  of  their  burrows  with  leaves. 
One  of  their  strongest  instincts  is  the  plug- 
ging up  the  mouths  of  their  burrows  with 
various  objects ;  and  very  young  worms  act 
in  this  manner.  But  some  degree  of  in- 
telligence appears,  as  we  shall  see  in  the  next 
chapter,  to  be  exhibited  in  this  work, — a 
result  which  has  surprised  me  more  than 
anything  else  in  regard  to  worms. 

Food  and  Digestion. — Worms  are  omnivo- 
rous. They  swallow  an  enormous  quantity  of 
earth,  out  of  which  they  extract  any  diges- 
tible matter  which  it  may  contain ;  but  to 
this  subject  I  must  recur.  They  also  con- 
sume a  large  number  of  half-decayed  leaves 
of  all  kinds,  excepting  a  few  which  have  an 
unpleasant  taste  or  are  too  tough  for  them  : 


36  HABITS  OF   WORMS.  Chap.  1 

likewise  petioles,  peduncles  and  decayed 
flowers.  But  they  will  also  consume  fresh 
leaves,  as  T  have  found  by  repeated  trials. 
According  to  Morren*  they  will  eat  particles 
of  sugar  and  liquorice  ;  and  the  worms  which 
I  kept  drew  many  bits  of  dry  starch  into 
their  burrows,  and  a  large  bit  had  its  angles 
well  rounded  by  the  fluid  poured  out  of  their 
mouths.  But  as  they  often  drag  particles  of 
soft  stone,  such  as  of  chalk,  into  their  burrows, 
I  feel  some  doubt  whether  the  starch  was 
used  as  food.  Pieces  of  raw  and  roasted  meat 
were  fixed  several  times  by  loug  pins  to  the 
surface  of  the  soil  in  my  pots,  and  night  after 
night  the  worms  could  be  seen  tugging  at 
them,  with  the  edges  of  the  pieces  engulfed 
in  their  mouths,  so  that  much  was  consumed. 
Raw  fat  seems  to  be  preferred  even  to  raw 
meat  or  to  any  other  substance  which  was 
given  them,  and  much  was  consumed.  They 
are  cannibals,  for  the  two  halves  of  a  dead 
worm  placed  in  two  of  the  pots  were  dragged 
into  the  burrows  and.  gnawed ;  but  as  far  as 
I  could  judge,  they  prefer  fresh  to  putrid 
meat,  and  in  so  far  I  differ  from  Hofirneister. 

*  '  De  Lumbrici  terrestris  '  p.  19. 


CiiAP.  I.  FOOD   AND   DIGESTION.  37 

Leon  Fredericq  states*  that  tlie  digestive 
fluid  of  worms  is  of  tlie  same  natm^e  as  the 
pancreatic  secretion  of  the  higher  animals ; 
and  this  conclusion  agrees  perfectly  with  the 
kinds  of  food  which  worms  consume.  Pan- 
creatic juice  emulsifies  fat,  and  we  have  just 
seen  how  greedily  worms  devour  fat ;  it 
dissolves  fibrin,  and  worms  eat  raw  meat ;  it 
converts  starch  into  grape-sugar  with  wonder- 
ful rapidity,  and  vtq  shall  presently  show  that 
the  digestive  fluid  of  worms  acts  on  starch.f 
But  they  live  chiefly  on  half-decayed  leaves ; 
and  these  would  be  useless  to  them  unless  they 
could  digest  the  cellulose  forming  the  cell- 
walls  ;  for  it  is  well  known  that  all  other  nutri- 
tious substances  are  almost  completely  with- 
drawn from  leaves,  shortly  before  they  fall 
off.  It  has,  however,  now  been  ascertained 
that  cellulose,  though  very  little  or  not  at  all 
attacked  by  the  gastric  secretion  of  the  higher 
animals,  is  acted  on  by  that  from  the  pancreas.  J 

•  *  Arcliives  de  Zoologie  experimentale/  torn.  vii.  1878,  p.  394. 

t  On  the  action  of  the  pancreatic  ferment,  see  *  A  Text-Book 
cf  Physiology,' by  Michael  Foster,  2n(i  edit.  pp.  198-203.    1878. 

X  Schmulewitsch,  '  Action  des  Sues  digestifs  sur  la  Cellulose. 
Bull,  de  I'Acad.  Imp.  de  St.  Pe'teisbourg,  torn.  xxv.  p.  549. 
1879. 


38  HABITS   OF   WORMS.  Chap.  1 

The  half-decayed  or  fresh  leaves  which 
worms  intend  to  devour,  are  dragged  into  the 
mouths  of  their  burrows  to  a  depth  of  from 
one  to  three  inches,  and  are  then  moistened 
with  a  secreted  fluid.  It  has  been  assumed 
that  this  fluid  serves  to  hasten  their  decay ; 
but  a  large  number  of  leaves  were  twice 
pulled  out  of  the  burrows  of  worms  and  kept 
for  many  weeks  in  a  Yerj  rnoist  atmosphere 
under  a  bell-glass  in  my  study ;  and  the  parts 
which  had  been  moistened  by  the  worms  did 
not  decay  more  quickly  in  any  plain  manner 
than  the  other  parts.  When  fresh  leaves 
were  given  in  the  evening  to  worms  kept  in 
confinement  and  examined  early  on  the  next 
morning,  therefore  not  many  hours  after  they 
had  been  dragged  into  the  burrows,  the  fluid 
with  which  they  were  moistened^  when  tested 
with  neutral  litmus  paper,  showed  an  alkaline 
reaction.  This  was  repeatedly  found  to  be 
the  case  with  celery,  cabbage  and  turnip 
leaves.  Parts  of  the  same  leaves  which  had 
not  been  moistened  by  the  worms,  were 
pounded  with  a  few  drops  of  distilled  water, 
and  tlie  juice  thus  extracted  was  not  alkaline. 
Some  leaves,  however,  which  had  been  drawn 


CiiAP.  I.  FOOD   AND   DIGESTION.  39 

into  burrows  out  of  doors,  at  an  unknown 
antecedent  period,  were  tried,  and  though  still 
moist,  they  rarely  exhibited  even  a  trace  of 
alkaline  reaction. 

The  fluid,  with  which  the  leaves  are  bathed, 
acts  on  thein  whilst  they  are  fresh  or  nearly 
fresh,  in  a  remarkable  manner ;  for  it  quickly 
kills  and  discolours  them.  Thus  the  ends  of 
a  fresh  carrot-leaf,  which  had  been  dragged 
into  a  burrow,  were  found  after  twelve  hours 
of  a  dark  brown  tint.  Leaves  of  celery, 
turnip,  maple,  elm,  lime,  thin  leaves  of  ivy, 
and  occasionally  those  of  the  cabbage  were 
similarly  acted  on.  The  end  of  a  leaf  of 
Triticum  repens^  still  attached  to  a  growing 
plant,  had  been  drawn  into  a  burrow,  and 
this  part  was  dark  brown  and  dead,  whilst  the 
rest  of  the  leaf  was  fresh  and  green.  Several 
leaves  of  lime  and  elm  removed  from  burrows 
out  of  doors  were  found  affected  in  different 
degrees.  The  first  change  appears  to  be  that 
the  veins  become  of  a  dull  reddish-orange. 
The  cells  with  chlorophyll  next  lose  more  or 
less  completely  their  green  colour,  and  their 
contents  finally  become  brown.  The  parts 
thus  affected  often  appeared  almost  black  by 


4:0  HABITS   OF   WORMS.  Cuap.  L 

reflected  light;  but  when  viewed  as  a  trans- 
parent object  under  the  microscope,  minute 
specks  of  h'ght  were  transmitted,  and  this 
was  not  the  case  with  the  unaffected  parts 
of  the  same  leaves.  These  effects,  how^- 
ever,  merely  show  that  the  secreted  fluid  is 
highly  injurious  or  poisonous  to  leaves ;  for 
nearly  the  same  effects  were  produced  in  from 
one  to  two  days  on  various  kinds  of  young 
leaves,  not  only  by  artificial  pancreatic  fluid, 
prepared  with  or  without  thymol,  but  quickly 
by  a  solution  of  thymol  by  itself.  On  one 
occasion  leaves  of  Corylus  were  much  dis- 
coloured by  being  kept  for  eighteen  hours  in 
pancreatic  fluid,  without  any  thymol.  With 
young  and  tender  leaves  immersion  in  human 
saliva  during  rather  warm  weather,  acted  in 
the  same  manner  as  the  pancreatic  fluid,  but 
not  so  quickly.  The  leaves  in  all  these  cases 
often  became  infiltrated  with  the  fluid. 

Large  leaves  from  an  ivy  plant  growing 
on  a  wall  were  so  tough  that  they  could  not 
be  gnawed  by  worms,  but  after  four  days 
Ihey  were  affected  in  a  peculiar  manner  by  the 
secretion  poured  out  of  their  mouths.  The 
upper  surfaces  of  the  leaves,  over  which  the 


Chap.  I.  FOOD   AND   DIGESTION.  41 

worms  had  crawled,  as  was  sliown  by  the  dirt 
left  on  them,  were  marked  in  sinuous  lines, 
by  either  a  continuous  or  broken  chain  of 
whitish  and  often  star-shaped  dots,  about 
2  mm.  in  diameter.  The  appearance  thus  pre- 
sented was  curiously  like  that  of  a  leaf,  into 
which  the  larva  of  some  minute  insect  had 
burrowed.  But  my  son  Francis,  after  making 
and  examining  sections,  could  nowhere  find 
that  the  cell-walls  had  been  broken  down  or 
that  the  epidermis  had  been  penetrated. 
When  the  section  passed  through  the  whitish 
dots,  the  grains  of  chlorophyll  were  seen  to 
be  more  or  less  discoloured,  and  some  of  the 
palisade  and  mesophyll  cells  contained 
nothing  but  broken  down  granular  matter. 
These  effects  must  be  attributed  to  the  trans- 
udation of  the  secretion  through  the  epidermis 
into  the  cells. 

The  secretion  with  which  worms  moisten 
leaves  likewise  acts  on  the  starch  granules 
within  the  cells.  My  son  examined  some 
leaves  of  the  ash  and  many  of  the  lime, 
which  had  fallen  off  the  trees  and  had  been 
partly  dragged  into  worm-burrows.  It  is 
known  that  with   fallen   leaves   the    starch- 


42  HABITS   OF   WOEMS.  Chap.  L 

grains  are  preserved  in  the  guard-cells  of  tlie 
storaata.  Now  in  several  cases  the  starch  had 
partially  or  wholly  disappeared  from  these 
cells,  in  the  parts  which  had  been  moistened  by 
tlie  secretion ;  while  they  were  still  well  pre- 
served in  the  other  parts  of  the  same  leaves. 
Sometimes  the  starch  was  dissolved  out  of 
only  one  of  the  two  guard- eel  Is.  The 
nucleus  in  one  case  had  disappeared,  together 
with  the  starch-granules.  The  mere  burying 
of  lime-leaves  in  damp  earth  for  nine  days 
did  not  cause  the  destruction  of  the  starch- 
granules.  On  the  other  hand,  the  immersion 
of  fresh  lime  and  cherry  leaves  for  eighteen 
hours  in  artificial  pancreatic  fluid,  led  to  the 
dissolution  of  the  starch-granules  in  the  guard- 
cells  as  well  as  in  the  other  cells. 

From  the  secretion  with  which  the  leaves 
are  moistened  being  alkaline,  and  from  its 
acting  both  on  the  starch-granules  and  on 
the  protoplasmic  contents  of  the  cells,  we 
may  infer  that  it  resembles  in  nature  not 
saliva,*  but  pancreatic  secretion ;  and  we 
know  from  Fredericq  that  a  seci^etion  of  tiiis 

*  C/laparede  doubts  whether  saliva  is  secretea  by  worms :  see 
Zeitschiift  fiir  wissenschaft.  Zoologie,'  P>.  xix.  1869,  p.  GOl. 


Chap.  I.  CALCIFEROUS   GLANDS.  43 

kind  is  found  in  the  intestines  of  worms.  As 
the  leaves  whicli  are  dragged  into  tlie  bur- 
rows are  often  dry  and  shrivelled,  it  is  in- 
dispensable for  their  disintegration  by  the 
unarmed  mouths  of  worms  that  they  should 
first  be  moistened  and  softened  ;  and  fresh 
leaves,  however  soft  and  tender  they  may  be, 
are  similarly  treated,  probably  from  habit. 
The  result  is  that  they  are  partially  digested 
before  they  are  taken  into  the  alimentary 
canal.  I  am  not  aware  of  any  other  case  of 
extra-stomachal  digestion  having  been  re- 
corded. The  boa-constrictor  bathes  its  prey 
with  saliva^  but  this  is  solely  for  lubricating 
it.  Perhaps  the  nearest  analogy  may  be 
found  in  such  plants  as  Drosera  and  Dionasa ; 
for  here  animal  matter  is  digested  and  con- 
verted into  peptone  not  within  a  stomach,  but 
on  the  surfaces  of  the  leaves. 

Calciferous  Glaiids. — These  glands  (see 
Fig.  1),  judging  from  their  size  and  from  their 
rich  supply  of  blood-vessels,  must  be  of  much 
importance  to  the  animal.  But  almost  aa 
many  theories  have  been  advanced  on  their 
use  as  there  have  been  observers.  They 
consist  of  three  pairs,  which  in  the  common 


14  HABITS   OF  WORMS.  Chap.  T. 

earth-worm  debouch  into  the  ahmentary 
canal  in  advance  of  the  gizzard,  but  pos- 
teriorly to  it  in  Urochtsea  and  some  other 
genera.*  The  two  posterior  pairs  are  formed 
by  lamellge,  which  according  to  Claparede, 
are  diverticula  from  the  oesophagus. y  These 
lamellae  are  coated  with  a  pulj)y  cellular 
layer,  with  the  outer  cells  lying  free  in  in- 
finite numbers.  If  one  of  these  glands  is 
punctured  and  squeezed,  a  quantity  of  white 
pulpy  matter  exudes,  consisting  of  these  free 
cells.  They  are  minute,  and  vary  in  diameter 
from  2  to  6  /^.  They  contain  in  their  centres  a 
little  excessively  fine  granular  matter;  but 
they  look  so  like  oil  globules  that  Claparede 
and  others  at  first  treated  them  with  ether. 
This  produces  no  effect ;  but  they  are  quickly 
dissolved  with  effervescence  in  acetic  acid, 
and  when  oxalate  of  ammonia  is  added 
to  the  solution  a  white  precipitate  is  thrown 
down.  We  may  therefore  conclude  that 
they  contain  carbonate  of  lime.     If  the  cells 


*  Perrier,  '  Archives  de  Zoolog.  exp^r,'  July,  1874,  pp.  416, 
419. 

t  '  Zeitschrift  fiir  wissenschaft.  Zoologie,'  B.  xix.  18G9,  pp, 
603-606. 


Chap.  I.  CALCIFEROUS   GLANDS.  45 

are  immersed  in  a  very  little  acid,  they 
become  more  transparent,  look  like  ghosts, 
and  are  soon  lost  to  view ;  but  if  much  acid 
is  added,  they  disappear  instantly.  After  a 
very  large  number  have  been  dissolved,  a 
flocculent  residue  is  left,  which  apparently 
consists  of  the  delicate  ruptured  cell-walls. 
In  the  two  posterior  pairs  of  glands  the 
carbonate  of  lime  contained  in  the  cells  oc- 
casionally aggregates  into  small  rhombic 
crystals  or  nito  concretions,  which  lie  be- 
tween the  lamellae ;  but  I  have  seen  only  one, 
and  Claparede  only  a  very  few  such  cases. 

The  two  anterior  glands  differ  a  little  in 
shape  from  the  four  posterior  ones,  by  being 
more  oval.  They  differ  also  conspicuously  in 
generally  containing  several  small,  or  two  or 
three  larger,  or  a  single  very  large  concre- 
tion of  carbonate  of  lime,  as  much  as  IJ  mm. 
in  diameter.  When  a  gland  includes  only 
a  few  very  small  concretions,  or,  as  sometimes 
happens,  none  at  all,  it  is  easily  overlooked. 
The  large  concretions  ai'e  round  or  oval,  and 
exteriorly  almost  smooth.  One  was  found 
which  filled  up  not  only  the  whole  gland,  as 
is   often  the  case,  but  its    neck  ;    so   that   it 


46  HABITS   OF   WORMS.  Chap.  L 

resembled  an  olive-oil  flask  in  shape.  These 
concretions  when  broken  are  seen  to  be 
more  or  less  crystalline  in  structure.  How 
they  escape  from  the  gland  is  a  marvel ;  but 
tliat  they  do  escape  is  certain,  for  they  are 
often  found  in  the  gizzard,  intestines,  and 
in  the  castings  of  worms,  both  with  those 
kept  in  confinement  and  those  in  a  state  of 
nature. 

Claparede  says  very  little  about  the 
structure  of  the  two  anterior  glands,  and  he 
supposes  that  the  calcareous  matter  of  which 
the  concretions  are  formed  is  derived  from 
the  four  posterior  glands.  But  if  an  anterior 
gland  which  contains  only  small  concretions 
is  placed  in  acetic  acid  and  afterwards 
dissected,  or  if  sections  are  made  of  such 
a  gland  without  being  treated  with  acid, 
lamellae  like  those  in  the  posterior  glands 
and  coated  with  cellular  matter  could  be 
plainly  seen,  together  with  a  multitude  of 
free  calciferous  cells  readily  soluble  in  acetic 
acid.  When  a  gland  is  completely  filled  with 
a  single  large  concretion,  there  are  no  free 
cells,  as  these  have  been  all  consumed  in 
forming  the  concretion.     But  if  such  a  c(m- 


<^nAP.  I.  CALCIFEllOUS   GLANDS.  47 

cretion,  or  one  of  only  moderately  large  size 
is  dissolved  in  acid,  mncli  membranous  matter 
is  left,  which  appears  to  consist  of  the  remains 
of  the  formerly  active  lamellae.  After  the 
formation  and  expulsion  of  a  large  concretion, 
new  lamellae  must  be  developed  in  some 
manner.  In  one  section  made  by  my  son,  the 
process  had  apparently  commenced,  although 
the  gland  contained  two  rather  large  concre- 
tions, for  near  the  walls  several  cylindrical 
and  oval  pipes  were  intersected,  which  were 
lined  with  cellular  matter  and  were  quite 
filled  with  free  calciferous  cells.  A  great 
enlargement  in  one  direction  of  several  oval 
pipes  would  give  rise  to  the  lamellse. 

Besides  the  free  calciferous  cells  in  which 
no  nucleus  was  visible,  other  and  rather 
larger  free  cells  were  seen  on  three  occasions ; 
and  these  contained  a  distinct  nucleus  and 
nucleolus.  They  were  only  so  far  acted  on 
by  acetic  acid  that  the  nucleus  was  thus 
rendered  more  distinct.  A  very  small  con- 
cretion was  removed  from  between  two  of  the 
lamellae  within  an  anterior  gland.  It  was 
embedded  in  pulpy  cellular  matter,  with 
many  free  calciferous  cells,  together  with   a 


i8  HABITS   OF   WOKMS.  Chap,  h 

multitude  of  the  larger,  free,  nucleated  cells, 
aud  these  latter  cells  were  not  acted  on  by 
acetic  acid,  while  the  former  were  dissolved. 
From  this  and  other  such  cases  I  am  led  to 
suspect  that  the  calciferous  cells  are  developed 
from  the  larger  nucleated  ones ;  but  how 
this  is  effected  was  not  ascertained. 

When  an  anterior  gland  contains  several 
minute  concretions,  some  of  these  are  generally 
angular  or  crystalline  in  outline,  while  the 
greater  number  are  rounded  with  an  irregu- 
lar mulberry-like  surface.  Calciferous  cells 
adhered  to  many  parts  of  these  mulberry-like 
masses,  and  their  gradual  disappearance  could 
be  traced  while  they  still  remained  attached. 
It  was  thus  evident  that  the  concretions  are 
formed  from  the  lime  contained  within  the 
free  calciferous  cells.  As  the  smaller  concre- 
tions increase  in  size,  they  come  into  contact 
and  unite,  thus  enclosing  the  now  functionless 
lamellge ;  and  by  such  steps  the  formation  of 
the  largest  concretions  could  be  followed. 
Why  the  process  regularly  takes  place  in  th© 
two  anterior  glands,  and  only  rarely  in  the 
four  posterior  glands  is  quite  unknown. 
Morren    says    that    these    glands    disappear 


Chap.  I.  CALCIFEROUS   GLANDS.  49 

during  the  winter  ;  and  I  have  seen  some 
instances  of  this  fact,  and  others  in  which 
either  the  anterior  or  posterior  glands  were 
at  this  season  so  shrunk  and  empty,  ttiat 
they  could  be  distinguished  only  with  much 
difficulty. 

With  respect  to  the  function  of  the  calci- 
ferous  glands,  it  is  probable  that  they  pri- 
marily serve  as  organs  of  excretion,  and 
secondarily  as  an  aid  to  digestion.  Worms 
consume  many  fallen  leaves ;  and  it  is  known 
that  lime  goes  on  accumulating  in  leaves  until 
they  drop  off  the  parent-plant,  instead  of 
being  re-absorbed  into  the  stem  or  roots,  like 
various  other  organic  and  inorganic  sub- 
stances.'^ The  ashes  of  a  leaf  of  an  acacia 
have  been  known  to  contain  as  much  as 
Y2  per  cent,  of  lime.  Worms  therefore  would 
be  liable  to  become  charged  with  this  earth, 
unless  there  were  some  special  means  for  its 
excretion ;  and  the  calciferous  glands  are 
well  adapted  for  this  purpose.  The  worms 
which  live  in  mould  close  over  the  chalk, 
often  have  their  intestines  filled  with  this 
substance,  and  their  castings  are  almost  white. 

*  De  Vries,  '  Landwirth.  Jahrbiicher,'  1881,  p.  77. 


50  HABITS   OF   WORMS.  Chap.  L 

Here  it  is  evident  that  the  supply  of  cal- 
careous matter  must  be  superabundant, 
Nevertheless  with  several  worms  collected  on 
such  a  site,  the  calciferous  glands  contained 
as  many  free  calciferous  cells,  and  fully  as 
many  and  large  concretions,  as  did  the 
glands  of  worms  which  lived  where  there  was 
little  or  no  lime ;  and  this  indicates  that  the 
lime  is  an  excretion,  and  not  a  secretion 
poured  into  the  alimentary  canal  for  some 
special  purpose. 

On  the  other  hand,  the  following  considera- 
tions render  it  highly  probable  that  the 
carbonate  of  lime,  which  is  excreted  by  the 
glands,  aids  the  digestive  process  under 
ordinary  circumstances.  Leaves  during  their 
decay  generate  an  abundance  of  various  kinds 
of  acids,  which  have  been  grouped  together 
under  the  term  of  humus  acids.  We  shall 
have  to  recur  to  this  subject  in  our  fifth 
chapter,  and  I  need  here  only  say  that  these 
acids  act  strongly  on  carbonate  of  lime.  The 
half-decayed  leaves  which  are  swallowed  in 
such  large  quantities  by  worms  would,  there- 
fore, after  they  have  been  moistened  and 
triturated  in  the  alimentary  canal,  be  apt  to 


Chap.  I.  CALCIFEROUS   GLANDS.  5i 

produce  such  acids.  And  in  the  case  of 
several  worms,  the  contents  of  the  alimentary 
canal  were  found  to  be  plainly  acid,  as  shown 
by  litmus  paper.  This  acidity  cannot  be 
attributed  to  the  nature  of  the  digestive  fluid, 
for  pancreatic  fluid  is  alkaline ;  and  we  have 
seen  that  the  secretion  which  is  poured  out  of 
the  mouths  of  worms  for  the  sake  of  pre- 
paring the  leaves  for  consumption,  is  likewise 
alkaline.  The  acidity  can  hardly  be  due  to 
uric  acid,  as  the  contents  of  the  upper  part  of 
the  intestine  were  often  acid.  In  one  case 
the  contents  of  the  gizzard  were  slightly  acid, 
those  of  the  upper  intestines  being  more 
plainly  acid.  In  another  case  the  contents  of 
the  pharynx  were  not  acid,  those  of  tlie 
gizzard  doubtfully  so,  while  those  of  the  in- 
testine were  distinctly  acid  at  a  distance  of 
5  cm.  below  the  gizzard.  Even  with  the 
higher  herbivorous  and  omnivorous  animals, 
the  contents  of  the  large  intestine  are  acid. 
"  This,  however,  is  not  caused  by  any  acid 
''  secretion  from  the  mucous  membrane  ;  the 
"  reaction  of  the  intestinal  walls  in  the  larger 
'^  as  in  the  small  intestine  is  alkaline.  It 
*'  must  therefore  arise  from  acid  fermentations 


52  HABITS   OF   WORMS.  Chap.  I. 

"  going  on  in  the  contents  themselves.  .  .  . 
*'  In  Garni vora  the  contents  of  the  coecum 
"  are  said  to  be  alkahne,  and  naturally  the 
*•  amount  of  fermentation  will  depend  largely 
"  on  the  nature  of  the  food."* 

With  worms  not  only  the  contents  of  the 
intestines,  but  their  ejected  matter  or  the 
castings,  are  generally  acid.  Thirty  castings 
from  different  places  were  tested,  and  with 
three  or  four  exceptions  were  found  to  be 
acid ;  and  the  exceptions  may  have  been  due 
to  such  castings  not  having  been  recently 
ejected ;  for  some  which  were  at  first  acid, 
were  on  the  following  morning,  after  being 
dried  and  again  moistened,  no  longer  acid  ; 
and  this  probably  resulted  from  the  humus 
acids  being,  as  is  known  to  be  the  case,  easily 
decomposed.  Five  fresh  castings  from  worms 
which  lived  in  mould  close  over  the  chalk, 
were  of  a  whitish  colour  and  abounded  with 
calcareous  matter ;  and  these  were  not  in 
the  least  acid.  This  shows  how  effectually 
carbonate  of  lime  neutralises  the  intestinal 
acids.      When  worms  were  kept  in  pots  filled 

•  M.  Foster,  'A  Text-Book  of  Physiology,'  2iid  edit.  1878, 
p  243. 


CuAP.  I.  CALCIFEEOUS   GLANDS.  53 

with  fine  ferruginous  sand,  it  was  manifest 
that  the  oxide  of  iron,  with  which  the  grains 
of  silex  were  coated,  had  been  dissolved  and 
removed  from  them  in  the  castings. 

The  digestive  fluid  of  worms  resembles  Id 
its  action,  as  already  stated,  the  pancreatic 
secretion  of  the  higher  animals ;  and  in  these 
latter,  "  pancreatic  digestion  is  essentially 
''  alkaline  ;  the  action  will  not  take  place 
"  unless  some  alkali  be  present ;  and  the 
^'  activity  of  an  alkaline  juice  is  arrested  by 
"  acidification,  and  hindered  by  neutraliza- 
"  tion."*  Therefore  it  seems  highly  probable 
that  the  innumerable  calciferous  cells,  which 
are  poured  from  the  four  posterior  glands 
into  the  alimentary  canal  of  worms,  serve  to 
neutralise  more  or  less  completely  the  acids 
there  generated  by  the  half-decayed  leaves. 
We  have  seen  that  these  cells  are  instantly 
dissolved  by  a  small  quantity  of  acetic  acid, 
and  as  they  do  not  always  sufiSce  to  neu- 
tralise the  contents  of  even  the  upper  part  of 
the  alimentary  canal,  the  lime  is  perhaps 
aggregated  into  concretions  in  the  anterior 
pair  of  glands,  in  order  that  some  may  be 

*  M.  Foster,  Ibid.  p.  200. 


54  HABITS   OF   WOEMS.  (Jiiap.  I. 

carried  down  to  the  posterioi  parts  of  the 
intestine,  where  these  concretions  would  be 
rolled  about  amongst  the  acid  contents.  Tho 
concretions  found  in  the  intestines  and  in  tho 
castings  often  have  a  worn  appearance,  but 
whether  this  is  due  to  some  amount  of 
attrition  or  of  chemical  corrosion  could  not 
be  told.  Claparede  believes  that  they  are 
formed  for  the  sake  of  acting  as  mill-stones, 
and  of  thus  aiding  in  the  trituration  of  the 
food.  They  may  give  some  aid  in  this  way  ; 
but  I  fully  agree  with  Perrier  that  this  must 
be  of  quite  subordinate  importance,  seeing 
that  the  object  is  already  attained  by  stones 
being  generally  present  in  the  gizzards  and 
intestines  of  worms. 


CHAPTER  II. 

HABITS  OF  WORMS — Continued, 

Jidanner  in  whicli  worms  seize  objects — Their  power  of  suction — ■ 
The  instinct  of  plugging  up  the  mouths  of  their  burrows — 
Stones  piled  over  the  burrows — ^The  advantages  thus  gained — 
Intelligence  shown  by  worms  in  their  manner  of  plugging  up 
their  burrows — Various  kinds  of  leaves  and  other  objects  thus 
used — Triangles  of  paper — Summary  of  reasons  for  believing 
that  worms  exhibit  some  intelligence — Means  by  which  they 
excavate  their  burrows,  by  pushing  away  the  earth  and  swal- 
lowing it — P^arth  also  swallowed  for  the  nutritious  matter 
which  it  contains — Depth  to  which  worms  burrow,  and  the 
construction  of  their  burrows — Burrows  lined  with  castings, 
and  in  the  upper  part  with  leaves — The  lowest  part  paved  with 
little  stones  or  seeds — Manner  in  which  the  castings  are 
ejected — The  collapse  of  old  burrows — Distribution  of  worms  — 
Tower-like  castings  in  Bengal — Gigantic  castings  on  the 
Nilgiri  Mountains — Castings  ejected  in  all  countries. 

In  the  pots  in  which  worms  were  ke]3t, 
leaves  were  pinned  down  to  the  soil,  and 
at  night  the  manner  in  which  they  were 
seized  could  be  observed.  The  worms  always 
endeavoured  to  drag  the  leaves  towards  their 
burrows;  and  they  tore  or  sucked  o£P  small 
fragments,  whenever  the    leaves  were   suffi- 


56  HABITS   OF   WOllMS.  C11A.P.  II 

ciently  tender.  They  generally  seized  the 
thin  edge  of  a  leaf  with  their  mouths,  between 
the  projecting  upper  and  lower  lip ;  the 
thick  and  strong  pharynx  being  at  the  same 
time,  as  Perrier  remarks,  pushed  forward 
within  their  bodies,  so  as  to  afford  a  point 
of  resistance  for  the  upper  lip.  In  the  case 
of  broad  flat  objects  they  acted  in  a  wholly 
different  manner.  The  pointed  anterior 
extremity  of  the  bod}^,  after  being  brought 
into  contact  with  an  object  of  this  kind,  was 
drawn  within  the  adjoining  rings,  so  that  it 
appeared  truncated  and  became  as  thick  as 
the  rest  of  the  body.  This  part  could  then 
be  seen  to  swell  a  little ;  and  this,  I  believe, 
is  due  to  the  pharynx  being  pushed  a  little 
forwards.  Then  by  a  sliglit  withdrawal  ol 
the  pharynx  or  by  its  expansion,  a  vacuum 
was  produced  beneath  the  truncated  slimy 
end  of  the  body  whilst  in  contact  with  the 
object ;  and  by  this  means  the  two  adhered 
fiiinly  together.*  That  under  these  circum- 
Btances  a  vacuum  was  produced  was  plainly 

*  Claparedc  remarks  ('  Zeitschrift  fiir  wissenschaft.  Zoolog. 
B.  19,  1869,  p.  602)  that  the  pharynx  appears  from  its  structuie 
to  be  adapted  for  suction. 


Ciup.  II.      THEIR   MANNEE   OF   PEEHENSION.       57 

seen  on  one  occasion,  wlien  a  large  worm 
lying  beneath  a  flaccid  cabbage  leaf  tried  to 
drag  it  away ;  for  the  surface  of  the  leaf 
directly  over  the  end  of  the  worm's  body 
became  deeply  pitted.  On  another  occasion 
a  worm  suddenly  lost  its  hold  on  a  flat  leaf; 
and  the  anterior  end  of  the  body  was  momen- 
tarily seen  to  be  cup-formed.  Worms  can 
attach  themselves  to  an  object  beneath  watei 
in  the  same  manner ;  and  I  saw  one  thus 
dragging  away  a  submerged  slice  of  an 
onion-bulb. 

The  edges  of  fresh  or  nearly  fresh  leaves 
affixed  to  the  ground  were  often  nibbled  by 
the  worms ;  and  sometimes  the  epidermis  and 
all  the  parenchyma  on  one  side  was  gnawed 
completely  away  over  a  considerable  space ; 
the  epidermis  alone  on  the  opposite  side 
being  left  quite  clean.  The  veins  were 
never  touched,  and  leaves  were  thus  some- 
times partly  converted  into  skeletons.  As 
worms  have  no  teeth  and  as  their  mouths 
consist  of  very  soft  tissue,  it  may  be  pre- 
sumed that  they  consume  by  means  of  suction 
the  edges  and  the  parenchyma  of  fresh 
leaves,  after  they  have  been  softened  by  the 


58  HABITS   OF   WORMS.  Chap.  IL 

digestive  fluid.  They  cannot  attack  such 
sirong  leaves  as  those  of  sea-kale  or  large 
and  thick  leaves  of  ivy ;  though  one  of  the 
latter  after  it  had  hecome  rotten  was  reduced 
in  parts  to  the  state  of  a  skeleton. 

Worms  seize  leaves  and  other  objects,  not 
only  to  serve  as  food,  but  for  plugging  up 
the  mouths  of  their  burrows  ;  and  this  is 
one  of  their  strongest  instincts.  Leaves  and 
petioles  of  many  kinds,  some  flower-pedun- 
cles, often  decayed  twigs  of  trees,  bits  of 
paper,  feathers,  tufts  of  wool  and  horse-hairs 
are  dragged  into  their  burrows  for  this  pur- 
pose. I  have  seen  as  many  as  seventeen 
petioles  of  a  Clematis  projecting  from  the 
mouth  of  one  burrow,  and  ten  from  the 
mouth  of  another.  Some  of  these  objects, 
such  as  the  petioles  just  named,  feathers,  &c,, 
are  never  gnawed  by  worms.  In  a  gravel 
walk  in  my  garden  I  found  many  hundred 
leaves  of  a  pine-tree  (P.  austriaca  or  nigin- 
cans)  drawn  by  their  bases  into  burrows. 
The  surfaces  by  which  these  leaves  are  articu- 
lated to  the  branches  are  shaped  in  as  pecu- 
liar a  manner  as  is  the  joint  between  the  leg- 
bones  of  a  quadruped ;  and  if  these  surfaces 


Chap.  II.      PROTECTION   OF   THEIR   BURROWS.       59 

had  been  in  the  least  gnawed,  the  fact  would 
have  been  immediately  visible,  but  there  was 
no  trace  of  gnawing.  Of  ordinary  dicotyle- 
donous leaves,  all  those  which  are  dragged 
into  burrows  are  not  gnawed.  I  have  seen 
as  many  as  nine  leaves  of  the  lime-tree 
drawn  into  the  same  burrow,  and  not  nearly 
all  of  them  had  been  gnawed ;  but  such 
leaves  may  serve  as  a  store  for  future  con- 
sumption. Where  fallen  leaves  are  abun- 
dant, many  more  are  sometimes  collected 
over  the  mouth  of  a  burrow  than  can  be 
used,  so  that  a  small  pile  of  unused  leaves  is 
left  like  a  roof  over  those  which  have  been 
partly  dragged  in. 

A  leaf  in  being  dragged  a  little  way  into 
a  cylindrical  burrow  is  necessarily  much 
folded  or  crumpled.  When  another  leaf  is 
drawn  in,  this  is  done  exteriorly  to  the  first 
one,  and  so  on  with  the  succeeding  leaves  ;  and 
finally  all  become  closely  folded  and  pressed 
together.  Sometimes  the  worm  enlarges  the 
mouth  of  its  burrow,  or  makes  a  fresh  one 
close  by,  so  as  to  draw  in  a  still  larger  number 
of  leaves.  They  often  or  generally  fill  up  the 
interstices  betw^een  the  drawn-in  leaves  with 


60  HABITS   OF   WORMS.  Chap.  IL 

moist  viscid  earth  ejected  from  their  bodies, 
and  thus  the  mouths  of  the  burrows  are 
securely  plugged.  Hundreds  of  such  plugged 
burrows  may  be  seen  in  many  places, 
especially  during  the  autumnal  and  early 
winter  months.  But,  as  will  hereafter  be 
shown,  leaves  are  dragged  into  the  burrows 
not  only  for  plugging  them  up  and  for  food, 
but  for  the  sake  of  lining  the  upper  part  or 
mouth. 

When  worms  cannot  obtain  leaves,  petioles, 
sticks,  &c.,  with  which  to  plug  up  the  mouths 
of  their  burrows,  they  often  protect  them  by 
little  heaps  of  stones;  and  such  heaps  of 
smooth  rounded  pebbles  may  frequently  be 
seen  on  gravel- walks.  Here  there  can  be  no 
question  about  food.  A  lady,  who  was  in- 
terested in  the  habits  of  worms,  removed  the 
little  heaps  of  stones  from  the  mouths  of 
several  burrows  and  cleared  the  surface  of  the 
ground  for  some  inches  all  round.  She  went 
out  on  the  following  night  with  a  lantern, 
and  saw  the  worms  with  their  tails  fixed  in 
their  burrows^  dragging  the  stones  inwards 
by  the  aid  of  their  mouths,  no  doubt  by 
suction.      ^' After  .two    nights    some    of  the 


Chap.  IL      PROTECIION   OF   THEIR   BURROWS.       61 

"  holes  liad  8  or  9  small  stones  over 
"them;  after  four  nights  one  had  about 
^'  30,  and  another  34  stones."*  One  stone 
which  had  been  dragged  over  the  gravel-walk 
to  the  mouth  of  a  burrow  weighed  two 
oances ;  and  this  proves  how  strong  worms 
are.  But  they  show  greater  strength  in  some- 
times displacing  stones  in  a  well-trodden 
gravel-walk  ;  that  they  do  so,  may  be  inferred 
from  the  cavities  left  by  the  displaced  stones 
being  exactly  filled  by  those  lying  over  the 
mouths  of  adjoining  burrows,  as  I  have  my- 
self observed. 

Work  of  this  kind  is  usually  performed 
during  the  night ;  but  I  have  occasionally 
known  objects  to  be  drawn  into  the  burrows 
during  the  day.  What  advantage  the  worms 
derive  from  plugging  up  the  mouths  of  their 
burrows  with  leaves,  &c.,  or  from  piling 
stones  over  them,  is  donbtful.  They  do  not 
act  in  this  manner  at  the  times  when  they 
eject  much  earth  from  their  burrows  ;  for  their 
castings  then  serve  to  cover  the  moutli. 
When   gardeners    wish    to    kill  worms  on  a 

•  An  account  of  her  observations  is  given  in  the  '  Gardeners 
Chronicle,'  March  28th,  1868,  p.  324. 


62  HABITS   OF   WORMS.  Chap.  II 

lawn,  it  is  necessary  first  to  brush  or  rake 
away  the  castings  from  the  surface,  in  order 
that  the  h'me-water  may  enter  the  burrows.* 
It  might  be  inferred  from  this  fact  that  the 
mouths  are  plugged  up  with  leaves,  &c.,  to 
prevent  the  entrance  of  water  during  heavy 
rain ;  but  it  may  be  urged  against  this  view 
that  a  few,  loose,  well-rounded  stones  are  ill- 
adapted  to  keep  out  water.  I  have  moreover 
seen  many  burrows  in  the  perpendicularly 
cut  turf-edgings  to  gravel-walks,  into  which 
water  could  hardly  flow,  as  well  plugged  as 
burrows  on  a  level  surface.  Can  the  plugs 
or  piles  of  stones  aid  in  concealing  tbe  bur- 
rows from  scolopenders,  which^  according 
to  Hoffmeister,  f  are  the  bitterest  enemies  of 
worms  ?  Or  may  not  worms  when  thus  pro- 
tected be  able  to  remain  with  safety  with 
their  heads  close  to  the  mouths  of  their  bur- 
rows, which  we  know  that  they  like  to  do, 
but  which  costs  so  many  of  them  their  lives? 
Or  may  not  the  plugs  check  the  free  ingress, 
of  the  lowest  stratum  of  air,  when  chilled  by 

*  London's  '  Gard.  Mag.'  xvii.  p.  216,  as  quoted  in  the  '  Cata* 
logue  of  the  British  Museum  Worms,'  1865,  p.  327. 
t  '  Familie  der  Regenwiirmer,'  p.  19. 


CSAP.  11.      PEOTECTION   OF   THEIK   BURKOWS.      63 

radiation  at  niglit,  from  the  surrounding 
ground  and  herbage.  I  am  inclined  to  be- 
lieve in  this  latter  view  ;  firstly,  because  when 
worms  were  kept  in  pots  in  a  room  with  a 
fire,  in  which  case  cold  air  could  not  enter  the 
burrows,  they  plugged  them  up  in  a  slovenly 
manner  ;  and  secondarily,  because  they  often 
coat  the  upper  part  of  their  burrows  with 
leaves,  apparently  to  prevent  their  bodies  from 
coming  into  close  contact  with  the  cold  damp 
earth.  But  the  phigging-up  process  may 
perhaps  serve  for  all  the  above  purposes. 

Whatever  the  motive  may  be,  it  appears 
that  worms  much  dislike  leaving  the  mouths 
of  their  burrows  open.  Nevertheless  they 
will  reopen  them  at  night,  whether  or  not 
they  can  afterwards  close  them.  Numerous 
open  burrows  may  be  seen  on  recently-dug 
ground,  for  in  this  case  the  worms  eject  their 
castings  in  cavities  left  in  the  ground,  or  in 
the  old  burrows,  instead  of  piling  them  over 
the  mouths  of  their  burrows,  and  they  cannot 
collect  objects  on  the  surface  by  which  the 
mouths  might  be  protected.  So  again  on  a 
recently  disinterred  pavement  of  a  Roman 
villa  at  Abinger  (hereafter  to  be  described^ 


64  HABITS   OF   WORMS.  Chap  II. 

the  worms  pertinaciously  opened  their  bur- 
rows almost  every  nighty  when  these  had 
been  closed  by  being  trampled  on,  although 
they  were  rarely  able  to  find  a  few  minute 
stones  wherewith  to  protect  them. 

Intelligence  shown  by  worms  in  their  manner 
of  plugging  up  their  burrows. — If  a  man  had  to 
plug  up  a  small  cylindrical  hole,  with  such 
objects  as  leaves,  petioles  or  twigs,  he  would 
drag  or  push  them  in  by  their  pointed  ends ; 
but  if  these  objects  were  very  thin  relatively 
to  the  size  of  the  hole,  he  Avould  probably 
insert  some  by  their  thicker  or  broader  ends. 
The  guide  in  his  case  would  be  intelligence. 
It  seemed  therefore  worth  while  to  observe 
carefully  how  worms  dragged  leaves  into 
their  burrows ;  whether  by  their  tips  or 
bases  or  middle  parts.  It  seemed  more  espe- 
cially desirable  to  do  this  in  the  case  of  plants 
not  natives  to  our  country ;  for  although  the 
habit  of  dragging  leaves  into  their  burrows 
is  undoubtedly  instinctive  with  worms,  yel 
instinct  could  not  tell  them  how  to  act  in 
the  case  of  leaves  about  which  their  pro- 
genitors knew  nothing.  If,  moreover,  worms 
acted  solely  through  instinct  or  an  unvary* 


Chap.  II.  THEIR   INTELLIGENCE.  65 

ing  inherited  impulse,  they  would  draw  all 
kinds  of  leaves  into  their  burrows  in  the 
same  manner.  If  they  have  no  such  definite 
instinct,  we  might  expect  that  chance  would 
determine  whether  the  tip,  base  or  middle  was 
seized.  If  both  these  alternatives  are  ex- 
cluded, intelHgence  alone  is  left ;  unless  the 
worm  in  each  case  first  tries  many  different 
methods,  and  follows  that  alone  which 
proves  possible  or  the  most  easy ;  but  to  act 
in  this  manner  and  to  try  different  methods 
makes  a  near  approach  to  intelligence. 

In  the  first  place  227  withered  leaves  of 
various  kinds,  mostly  of  English  plants,  were 
pulled  out  of  worm-burrows  in  several  places. 
Of  these,  181  had  been  drawn  into  the 
burrows  by  or  near  their  tips,  so  that  the 
foot-stalk  projected  nearly  upright  from  the 
mouth  of  the  burrow  ;  20  had  been  drawn  in 
by  their  bases,  and  in  tbis  case  the  tips  pro- 
jected from  the  burrows ;  and  26  had  been 
seized  near  the  middle,  so  that  these  had 
been  drawn  in  transversely  and  u-ere  much 
crumpled.  Therefore  80  per  cent,  (always 
using  the  nearest  whole 'number)  had  been 
drawn  in  by  the  tip,  9  per  cent,  by  the  base 


B^  HABITS   OF   WORMS.  Chap.  IL 

or  footstalk,  and  11  per  cent.  traDSversely  or 
by  the  middle.  This  alone  is  almost  suffi- 
cient to  show  that  chance  does  not  determine 
the  manner  in  which  leaves  are  dragged  into 
the  burrows. 

Of  the  above  227  leaves,  70  consisted  of 
the  ftillen  leaves  of  the  common  lime-tree, 
which  is  almost  certainly  not  a  native  of 
England.  These  leaves  are  .much  acumin- 
ated towards  the  tip,  and  are  very  broad  at 
the  base  with  a  w^ell-developed  foot-stalk. 
They  are  thin  and  quite  flexible  when  half- 
withered.  Of  the  70,  79  per  cent,  had  been 
drawn  in  by  or  near  the  tip ;  4  per  cent 
by  or  near  the  base  ;  and  17  per  cent,  trans- 
versely or  by  the  middle.  These  proportions 
agree  very  closely,  as  far  as  the  tip  is  con- 
cerned, with  those  before  given.  But  the  per- 
centage drawn  in  by  the  base  is  smaller,  which 
may  be  attributed  to  the  breadth  of  the  basal 
part  of  the  blade.  We  here,  also,  see  that  the 
presence  of  a  foot-stalk,  which  it  might  have 
been  expected  would  have  tempted  the  worms 
as  a  convenient  handle,  has  little  or  no  in- 
fluence in  determining  the  manner  in  which 
iime  leaves   are    dragged    into  the  burrows. 


Chap.  IL  THEIR   INTELIJGENCE.  67 

The  considerable  proportioi],  viz.^  17  per 
cent.,  drawn  in  more  or  less  transversely 
depends  no  doubt  on  the  flexibility  of  these 
half-decayed  leaves.  The  fact  of  so  many 
having  been  drawn  in  by  the  middle,  and  of 
some  few  having  been  drawn  in  by  the  base, 
renders  it  improbable  that  the  worms  first 
tried  to  draw  in  most  of  the  leaves  by  one  or 
both  of  these  methods,  and  that  they  after- 
wards drew  in  79  per  cent,  by  their  tips; 
for  it  is  clear  that  they  would  not  have  failed 
in  drawing  them  in  by  the  base  or  middle. 

The  leaves  of  a  foreign  plant  were  next 
searched  for,  the  blades  of  which  were  not 
more  pointed  towards  the  apex  than  towards 
the  base.  This  proved  to  be  the  case  with 
those  of  a  laburnum  (a  hybrid  between 
Cytisus  alpinus  and  laburnum)  for  on  doubling 
the  terminal  over  the  basal  half,  they  gene- 
rally fitted  exactly ;  and  when  there  was 
any  difference,  the  basal  half  was  a  little  the 
narrower.  It  might,  therefore,  have  been 
expected  that  an  almost  equal  number  of 
the>e  leaves  would  have  been  drawn  in  by  the 
tip  and  base,  or  a  slight  excess  in  favour  of 
the  latter.     But  of  73  leaves  (not  included  m 


t)8  HABITS   OF    WORMS.  CnAP.  IL 

the    first   lot    of  227)   pulled    out  of  worm- 
burrows,  63  per  cent,  had  been  drawn  in  by 
the  tip ;  27  per  cent,  by  the  base,  and  10  per 
cent,  transversely.     We  here  see  that  a  far 
larger    proportion,    viz.,   27    per    cent,    were 
drawn  in  by  the   base  than   in   the  case   of 
lime    leaves,  the    blades  of  which    are   very 
broad  at  the  base,  and  of  which  only  4  per 
cent,   had   thus   been    drawn   in.      We   may 
perhaps  account  for  the  fact  of  a  still  larger 
proportion  of  the  laburnum  leaves  not  hav- 
ing been  drawn  in  by   the  base,  by  worms 
having  acquired  the  habit  of  generally  draw 
ing   in  leaves  by  their  tips  and  thus  avoid- 
ing the  foot-stalk.     For  the  basal  m.argin  of 
the  blade  in  many  kinds  of  leaves   forms  a 
large  angle  with  the  foot-stalk  ;  and  if  such  a 
leaf  were  drawn  in  by  the  foot-stalk,  the  basal 
margin   would   come    abruptly    into    contact 
with  the  ground  on  each  side  of  the  burrow, 
and  would  render   the  drawing  in  of  the  leaf 
very  difiicult. 

Nevertheless  worms  break  through  their 
habit  of  ai^oiding  the  footstalk,  if  this  part 
offers  them  the  most  convenient  means  for 
drawing  leaves  into  their  burrows.    The  leaves 


Chai'.  ri.  THEIR   INTELLIGENCE.  69 

of  the  endless  hybridised  varieties  of  the 
Rhododendron  vary  much  in  shape ;  some  are 
narrowest  towards  the  base  and  others  to- 
wards the  apex.  After  they  have  fallen  off, 
the  blade  on  each  side  of  the  midrib  often 
becomes  curled  up  while  drying,  sometimes 
along  the  whole  length,  sometimes  chiefly 
at  the  base,  sometimes  towards  the  apex. 
Out  of  28  fallen  leaves  on  one  bed  of  peat  in 
my  garden,  no  less  than  23  were  narrower  in 
the  basal  quarter  than  in  the  terminal  quarter 
of  their  length ;  and  this  narrowness  was 
chiefly  due  to  the  curling  in  of  the  margins. 
Out  of  36  fallen  leaves  on  another  bed,  in 
which  different  varieties  of  the  Rhododendron 
grew,  only  17  were  narrower  towards  the 
base  than  towards  the  apex.  My  son  William, 
who  first  called  my  attention  to  this  case, 
picked  up  237  fallen  leaves  in  his  garden 
(where  the  Rhododendron  grows  in  the 
natural  soil)  and  of  these  65  per  cent,  could 
have  been  drawn  by  worms  into  their  bur- 
rows more  easily  by  the  base  or  foot-stalk 
than  by  the  tip ;  and  this  was  partly  due  to 
the  shape  of  the  leaf  and  in  a  less  degree 
to  the  curling  in   of  the  margins :    27    per 


70  HABITS   OF   WORMS.  .Chap.  IL 

cent,  could  have  been  drawn  in  more  easily 
by  the  tip  than  by  the  base :  and  8  per  cent, 
with  about  equal  ease  by  either  end.  The 
sliape  of  a  fallen  leaf  ought  to  be  judged 
of  before  one  end  has  been  drawn  into  a 
burrow,  for  after  this  has  happened,  the  free 
end,  whether  it  be  the  base  or  apex,  will  dry 
more  quickly  than  the  end  embedded  in  the 
damp  ground ;  and  the  exposed  margins  of 
the  free  end  will  consequently  tend  to  become 
more  curled  inwards  than  they  were  when 
the  leaf  was  first  seized  by  the  worm.  My 
son  found  91  leaves  which  had  been  dragged 
by  worms  into  their  burrows,  though  not  to  a 
great  depth ;  of  these  6Q  per  cent,  had  been 
drawn  in  by  the  base  or  foot-stalk ;  and  34 
per  cent,  by  the  tip.  In  this  case,  there- 
fore, the  worms  judged  with  a  considerable 
degree  of  correctness  how  best  to  draw  the 
withered  leaves  of  this  foreign  plant  into  their 
burrows;  notwithstanding  that  they  had  to 
depart  from  their  usual  habit  of  avoiding 
the  foot-stalk. 

On  the  gravel-w^alks  in  my  garden  a  very 
large  number  of  leaves  of  three  species  of 
Pinus  (P.  austriaca,  nigricars  and  sylvestri^) 


Chap.  IL  THEIR   INTELLIGENCE.  71 

are  regularly  drawn  into  the  mouths  of  worm- 
burrows.  These  leaves  consist  of  two  needles, 
which  are  of  considerable  length  in  the  two 
first  and  short  in  the  last  named  species,  and 
are  united  to  a  common  base  ;  and  it  is  by  this 
part  that  they  are  almost  invariably  drawn 
into  the  burrows.  I  have  seen  only  two  or 
at  most  three  exceptions  to  this  rule  with 
worms  in  a  state  of  nature.  As  the  sharply 
pointed  needles  diverge  a  little,  and  as  several 
leaves  are  drawn  into  the  same  burrow,  each 
tuft  forms  a  perfect  chevaux  de  frise.  On  two 
occasions  many  of  these  tufts  were  pulled  up 
in  the  evening,  but  by  the  following  morning 
fresh  leaves  had  been  pulled  in,  and  the 
burrows  were  again  well  protected.  These 
leaves  could  not  be  dragged  into  the  burrows 
to  any  depth,  except  by  their  bases,  as  a 
worm  cannot  seize  hold  of  the  two  needles  at 
the  same  time,  and  if  one  alone  were  seized 
by  the  apex,  the  other  would  be  pressed 
against  the  ground  and  would  resist  the 
entry  of  the  seized  one.  This  was  manifest 
in  the  above  mentioned  two  or  three  excep- 
tional cases.     In  order,  therefore  that  worma 

should  do  their   work  well,  they  must  drag 
6 


72  HABITS   OF   WOEMS.  Chap.  IL 

pine-leaves  into  their  burrows  by  tlieir  bases, 
where  the  two  needles  are  conjoined.  But 
how  they  are  guided  in  this  work  is  a  per- 
plexing question. 

This  difficulty  led  my  son  Francis  and  my- 
self to  observe  worms  in  confinement  during 
several  nights  by  the  aid  of  a  dim  light,  while 
they  dragged  the  leaves  of  the  above  named 
pines  into  their  burrows.  They  moved  the 
anterior  extremities  of  their  bodies  about  the 
leaves,  and  on  several  occasions  when  they 
touched  the  sharp  end  of  a  needle  they  with- 
drew suddenly  as  if  pricked.  But  I  doubt 
whether  they  were  hurt,  for  they  are  indif- 
ferent to  very  sharp  objects,  and  will  swallow 
even  rose-thorns  and  small  splinters  of  glass. 
It  may  also  be  doubted,  whether  the  sharp 
ends  of  the  needles  serve  to  tell  them  that 
this  is  the  wrong  end  to  seize ;  for  the  points 
were  cut  off  many  leaves  for  a  length  of 
about  one  inch,  and  fifty-seven  of  them  thus 
treated  were  drawn  into  the  burrows  by 
their  bases,  and  not  one  by  the  cut-off  ends. 
The  worms  in  confinement  often  seized  the 
needles  near  the  middle  and  drew  them  to- 
wards the  mouths  of  their  burrows ;  and  one 


CiiAP.  II.  THEIR   INTELLIGENCE.  73 

worm  tried  in  a  senseless  manner  to  drag 
tliem  into  the  burrow  by  bending  tbem. 
They  sometimes  collected  many  more  leaves 
over  the  mouths  of  their  burrows  (as  in  the 
case  formerly  mentioned  of  lime-leaves)  than 
could  enter  them.  On  other  occasions,  how- 
ever, they  behaved  very  differently ;  for  as 
soon  as  they  touched  the  base  of  a  pine-leaf, 
this  was  seized,  being  sometimes  completely  en- 
gulfed in  their  months,  or  a  point  very  near 
the  base  was  se^'zed,  and  the  leaf  was  then 
quickly  dragged  or  rather  jerked  into  their 
burrows.  It  appeared  both  to  my  son  and 
myself  as  if  the  worms  instantly  perceived 
as  soon  as  they  had  seized  a  leaf  in  the  proper 
manner.  Nine  such  cases  were  observed, 
but  in  one  of  them  the  worm  failed  to  drag 
the  leaf  into  its  burrow,  as  it  was  entangled 
by  other  leaves  lying  near.  In  another  case 
H  leaf  stood  nearly  upright  with  the  points  of 
the  needles  partly  inserted  into  a  burrow,  but 
how  placed  there  was  not  seen ;  and  then  the 
<vorm  reared  itself  up  and  seized  the  base, 
which  was  dragged  into  the  mouth  of  the 
burrow  by  bowing  the  whole  leaf.  On  the 
other  hand,  after  a  worm  had  seized  the  base 


74  HABITS   OF   WORMS.  Cuap.  IL 

of  a   leaf,  this  was  on  two  occasions  relin- 
quished from  some  unknown  motive. 

As  already  remarked,  the  habit  of  plugging 
up  the  mouths  of  the  burrows  with  various 
objects,  is  no  doubt  instinctive  in  worms ; 
and  a  very  young  one,  born  in  one  of  my 
pots_,  dragged  for  some  little  distance  a  Scotc;h- 
iir  leaf,  one  needle  of  which  was  as  long  and 
almost  as  thick  as  its  own  body.  No  species 
of  pine  is  endemic  in  this  part  of  England, 
it  is  therefore  incredible  that  the  proper 
manner  of  dragging  pine-leaves  into  the 
burrows  can  be  instinctive  with  our  worms. 
But  as  the  worms  on  which  the  above  obser- 
vations were  made,  were  dug  up  beneath  or 
near  some  pines,  which  had  been  planted 
there  about  forty  years,  it  was  desirable  to 
prove  that  their  actions  were  not  instinctive. 
Accordingly,  pine-leaves  were  scattered  on 
the  ground  in  places  far  removed  from  any 
pine-tree,  and  90  of  them  were  drawn  into 
the  burrows  by  their  bases.  Only  two  were 
drawn  in  by  the  tips  of  the  needles,  and  theso 
were  not  real  exceptions,  as  one  was  drawn 
in  for  a  very  short  distance,  and  the  two 
needles  of  the   other   cohered.      Otlier  pine- 


Chap.  IL  THEIR   INTELLIGENCD.  75 

leaves  were  given  to  worms  kept  in  pots  in  a 
warm  room,  and  here  the  result  was  different ; 
for  out  of  42  leaves  drawn  into  the  burrows, 
no  less  than  16  were  drawn  in  by  the  tips 
of  the  needles.  These  worms,  however, 
worked  in  a  careless  or  slovenly  manner  ; 
for  the  leaves  were  often  drawn  in  to  only 
a  small  depth  ;  sometimes  they  were  merely 
heaped  over  the  mouths  of  the  burrows,  and 
sometimes  none  were  drawn  in.  I  believe 
that  this  carelessness  may  be  accounted  for 
by  the  air  of  the  room  being  warm,  and  the 
worms  consequently  not  being  anxious  to  plug 
up  their  holes  effectually.  Pots  tenanted 
by  worms  and  covered  with  a  net  which 
allowed  the  entrance  of  cold  air,  were  left 
out  of  doors  for  several  nights,  and  now  72 
leaves  were  all  properly  drawn  in  by  their 
bases. 

It  might  perhaps  be  inferred  from  the  facts 
as  yet  given,  that  worms  somehow  gain  a 
general  notion  of  the  shape  or  structure  of 
pine  leaves,  and  perceive  that  it  is  necessary 
for  them  to  seize  the  base  where  the  two 
needles  are  conjoined.  But  the  following 
cases   make    this  more  than  doubtful.      The 


76  HABITS   OF   WORMS.  Chap.  IL 

tips  of  a  large  number  of  needles  of  P.  austriaca 
were  cemented  together  with  shell-lac  dis- 
solved in  alcohol,  and  were  kept  for  some 
days,  until,  as  I  believe,  all  odour  or  taste  had 
been  lost;  and  they  were  then  scattered  on 
the  ground  where  no  pine-trees  grew,  near 
burrows  from  which  the  plugging  had  been 
removed.  Such  leaves  could  have  been  drawn 
into  the  burrows  with  equal  ease  by  either 
end ;  and  judging  from  analogy  and  more 
especially  from  the  case  presently  to  be  given 
of  the  petioles  of  Clematis  montana^  I  expected 
that  the  apex  would  have  been  preferred. 
But  the  result  was  that  out  of  121  leaves  with 
the  tips  cemented,  which  were  drawn  into  bur- 
rows, 108  were  drawn  in  by  their  bases,  and 
only  13  by  their  tips.  Thinking  that  the 
worms  might  possibly  perceive  and  dislike  the 
smell  or  taste  of  the  shell-lac,  though  this 
was  very  improbable,  especially  after  the 
leaves  had  been  left  out  during  several  nights, 
the  tips  of  the  needles  of  many  leaves  were 
tied  together  with  fine  thread.  Of  leaves 
thus  treated  150  were  drawn  into  burrows — 
123  by  the  base  and  27  by  the  tied  tips;  so 
that  between  four  and  five  times  as  many  were 


Chap.  II.  THEIR   INTELLIGENCE.  77 

drawn  in  by  the  base  as  by  the  tip.  It  is 
possible  that  the  short  cnt-off  ends  of  the 
tliread  with  which  they  were  tied,  may  have 
tempted  the  worms  to  drag  in  a  larger  propor- 
tional number  by  the  tips  than  when  cement 
was  used.  Of  tlie  leaves  with  tied  and 
cemented  tips  taken  together  (271  in  number) 
85  per  cent,  were  drawn  in  by  the  base  and 
15  per  cent,  by  the  tips.  We  may  therefore 
infer  that  it  is  not  the  divergence  of  the  two 
needles  which  leads  worms  in  a  state  of  nature 
almost  invariably  to  drag  pine-leaves  into 
their  burrows  by  the  base.  Nor  can  it  be  the 
sharpness  of  the  points  of  the  needles  which 
determines  them ;  for,  as  we  have  seen,  many 
leaves  with  the  points  cut  off  were  drawn  in 
by  their  bases.  We  are  thus  led  to  conclude, 
that  with  pine-leaves  there  must  be  something 
attractive  to  worms  in  the  base,  notwithstand- 
ing that  few  ordinary  leaves  are  drawn  in  by 
the  base  or  footstalk. 

Petioles, — We  will  now  turn  to  the  petioles 
or  foot-stalks  of  compound  leaves,  after  the 
leaflets  have  fallen  off.  Those  from  Clematis 
montana,  which  grew  over  a  verandah,  were 
dragged  early  in  January  in  large  numbers 


78  HABITS   OF   WORMS.  Chap.  U. 

into  the  burrows  on  an  adjoining  gravel- 
walk,  lawn,  and  flower-bed.  These  petioles 
vary  from  2 J  to  4 J  inches  in  length,  are 
rigid  and  of  nearly  uniform  thickness,  except 
close  to  the  base  where  they  thicken  rather 
abruptly,  being  here  about  twice  as  thick  as 
in  any  other  part.  The  apex  is  somewhat 
pomted,  but  soon  withers  and  is  then  easily 
broken  off.  Of  these  petioles,  314  were  pulled 
out  of  burrows  in  the  above  specified  sites ; 
and  it  was  found  that  7G  per  cent,  had  been 
drawn  in  by  their  tips,  and  24  per  cent,  by 
their  bases  ;  so  that  those  drawn  in  by  the 
tip  were  a  little  more  than  thrice  as  many 
as  those  drawn  in  by  the  base.  Some  of  those 
extracted  from  the  well-beaten  gravel-walk 
were  kept  separate  from  the  others ;  and  of 
these  (59  in  number)  nearly  five  times  as 
many  had  been  drawn  in  by  the  tip  as  by 
the  base ;  whereas  of  those  extracted  from 
the  lawn  and  flower-bed,  where  from  the 
soil  yielding  more  easily,  less  care  would  be 
necessary  in  plugging  up  the  burrows,  the 
proportion  of  those  drawn  in  by  the  tip  (130) 
(io  those  drawn  in  by  the  base  (48)  was 
rather  less  than   three   to  one.     That  these 


CuAP.  II.  THEIR   INTELLIGENCE.  79 

petioles  had  been  dragged  into  the  burrows 
for  plugging  them  up,  and  not  for  food, 
was  manifest,  as  neither  end,  as  far  as  I 
could  see,  had  been  gnawed.  As  several 
petioles  are  used  to  plug  up  the  same  burrow, 
i.n  one  case  as  many  as  10,  and  in  another 
case  as  many  as  15,  the  worms  may  perhaps 
at  first  draw  in  a  few  by  the  thicker  end  so 
as  to  save  labour ;  but  afterwards  a  large 
majority  are  drawn  in  by  the  pointed  end,  in 
order  to  plug  up  the  hole  securely. 

The  fallen  petioles  of  our  native  ash-tree 
were  next  observed,  and  the  rule  with  most 
objects,  viz.,  that  a  large  majority  are  dragged 
into  the  burrows  by  the  more  pointed  end,  had 
not  here  been  followed ;  and  this  fact  much 
surprised  me  at  first.  These  petioles  vary  in 
length  from  5  to  8|  inches  ;  they  are  thick 
and  fieshy  towards  the  base,  whence  they 
taper  gently  towards  the  apex,  which  is  a  little 
enlarged  and  truncated  where  the  terminal 
leaflet  had  been  originally  attached.  Under 
some  ash-trees  growing  in  a  grass-field,  229 
petioles  were  pulled  out  of  worm  burrows 
early  in  January,  and  of  these  51*5  per  cent. 
had  been  drawn  in  by  the  base,  and  48 '5  per 


80  HABITS   OF   WORMS.  Ciiai-.  II. 

cent,  by  the  apex.  This  anomaly  was  how- 
ever readily  explained  as  soon  as  the  thick 
basal  part  was  examined  ;  for  in  78  out  of  103 
petioles,  this  part  had  been  gnawed  by  worms, 
just  above  the  horse-shoe  shaped  articulation. 
hi  most  cases  there  could  be  no  mistake  about 
the  gnawing  ;  for  ungnawed  petioles  which 
were  examined  after  being  exposed  to  the 
weather  for  eight  additional  weeks  had  not 
become  more  disintegrated  or  decayed  near 
the  base  than  elsewhere.  It  is  thus  evident 
that  the  thick  basal  end  of  the  petiole  is 
drawn  in  not  solely  for  the  sake  of  plugging 
ap  the  mouths  of  the  burrows,  but  as  food. 
Even  the  narrow  truncated  tij)s  of  some 
few  petioles  had  been  gnawed ;  and  this 
was  the  case  in  6  out  of  37  which  were 
examined  for  this  purpose.  Worms,  after 
having  drawn  in  and  gnawed  the  basal  end, 
often  push  the  petioles  out  of  their  burrows ; 
and  then  drag  in  fresh  ones,  either  by 
the  base  for  food,  or  by  the  apex  for  plug- 
ging up  the  mouth  more  effectually.  Thus, 
out  of  37  petioles  inserted  by  their  tips, 
5  had  been  previously  drawn  in  by  the 
base,  for  this  part  liad  been  gnawed.    Again, 


Chap.  IT.  THEIE   INTELLiaENCE.  81 

I  collected  a  handful  of  petioles  lying  loose 
on  the  ground  close  to  some  plugged-up  bur- 
rows, where  the  surface  was  thickly  strewed 
with  other  petioles  which  apparently  had 
never  been  touched  by  worms ;  and  14  out 
of  47  (i.e.  nearly  one-third),  after  having 
had  their  bases  gnawed  had  been  pushed 
out  of  the  burrows  and  were  now  lying  on 
the  ground.  From  these  several  facts  we 
may  conclude  that  worms  draw  in  some 
petioles  of  the  ash  by  the  base  to  serve  as 
food,  and  others  by  the  tip  to  plug  up  the 
mouths  of  their  burrows  in  the  most  efficient 
manner. 

The  petioles  of  Rohinia  pseudo-acacia  vary 
from  4  or  5  to  nearly  12  inches  in  length  ; 
they  are  thick  close  to  the  base  before  the 
softer  parts  have  rotted  off,  and  taper  much 
towards  the  upper  end.  They  are  so  flexible 
that  I  have  seen  some  few  doubled  up  and 
thus  drawn  into  the  burrows  of  worms.  Un- 
fortunately these  petioles  were  not  examined 
until  February,  by  which  time  the  softer  parts 
had  completely  rotted  off,  so  that  it  was  im- 
possible to  ascertain  whether  worms  had 
gnawed   the    bases,    though  this   is  in  itself 


82  HABITS   OF   WOKMS.  Chap.  II 

probable.  Out  of  121  petioles  extracted  from 
burrows  early  iu  February,  68  were  embedded 
by  the  base,  and  53  by  the  apex.  On 
February  5  all  the  petioles  which  had  been 
drawn  into  the  burrows  beneath  a  Robinia, 
were  pulled  up ;  and  after  an  interval  ot 
eleven  days,  35  petioles  had  been  again 
dragged  in,  19  by  the  base,  and  16  by  the 
apex.  Taking  these  two  lots  together,  56 
per  cent,  were  drawn  in  by  the  base,  and  44 
per  cent,  by  the  apex.  As  all  the  softer  parts 
had  long  ago  rotted  off,  we  may  feel  sure, 
especially  in  the  latter  case,  that  none  had 
been  drawn  in  as  food.  At  this  season,  there- 
fore, worms  drag  these  petioles  into  their 
burrows  indifferently  by  either  end,  a  slight 
preference  being  given  to  the  base.  This 
latter  fact  may  be  accounted  for  by  the  difiS- 
culty  of  plugging  up  a  burrow  with  objects  so 
extremely  thin  as  are  the  upper  ends.  In 
support  of  this  view,  it  may  be  stated  that  out 
of  the  16  petioles  which  had  been  drawn 
in  by  their  upper  ends,  the  more  attenuated 
terminal  portion  of  7  had  been  previously 
broken  off  by  some  accident. 

Triangles    of  paper, — Elongated    trianghjy 


Uhap.  II.  THEIR   INTELLIGENCE.  83 

were  cut  out  of  moderately  stiff  writing-paper, 
which  was  rubbed  with  raw  fat  on  both  sides, 
so  as  to  prevent  their  becoming  excessively 
limp  when  exposed  at  night  to  rain  and  dew. 
The  sides  of  all  the  triangles  were  three 
inches  in  length,  with  the  bases  of  120  one 
inch,  and  of  the  other  183  half  an  inch  in 
length.  These  latter  triangles  were  very 
narrow  or  much  acuminated.*  As  a  check 
on  the  observations  presently  to  be  given, 
similar  triangles  in  a  damp  state  were  seized 
by  a  very  narrow  pair  of  pincers  at  different 
points  and  at  all  inclinations  with  reference 
to  the  margins,  and  were  then  drawn  into 
a  short  tube  of  the  diameter  of  a  worm- 
burrow.  If  seized  by  the  apex,  the  triangle 
was  drawn  straight  into  the  tube,  with  its 
margins  infolded;  if  seized  at  some  little 
distance  from  the  apex,  for  instance  at  hall 
an  inch,  this  much  was  doubled  back  within 
the  tube.  So  it  was  with  the  base  and  basal 
angles,  though  in  this  case  the  triangles 
offered,  as    might  have  been  expected,  much 

•  In  tliese  narrow  triangles  the  apical  angle  is  9°  34',  and  the 
basal  angles  85°  13'.  In  the  broader  triangles  the  apical  angle  ia 
19°  !(/  and  the  basal  andes  80°  25'. 


84  HABITS   OF   WOllMS.  Chap.  II 

more  resistance  to  being  drawn  in.  If  seized 
near  tlie  middle  the  triangle  was  doubled  up, 
with  the  apex  and  base  left  sticking  out  of  the 
tube.  As  the  sides  of  the  triangles  were 
ihree  inches  in  length,  the  result  of  their 
being  drawn  into  a  tube  or  into  a  burrow  in 
different  ways,  may  be  conveniently  divided 
into  three  groups :  those  drawn  in  by  the 
apex  or  within  an  inch  of  it ;  those  drawn  in 
by  the  base  or  within  an  inch  of  it ;  and  those 
drawn  in  by  any  point  in  the  middle  inch. 

In  order  to  see  how  the  triangles  would  be 
seized  by  worms,  some  in  a  damp  state  were 
given  to  worms  kept  in  confinement.  They 
were  seized  in  three  different  manners  in  the 
case  of  both  the  narrow  and  broad  triangles  : 
viz.,  by  the  margin  ;  by  one  of  the  three 
angles,  which  was  often  completely  engulfed 
in  their  mouths  ;  and  lastly,  by  suction  applied 
to  any  part  of  the  flat  surface.  If  lines 
parallel  to  the  base  and  an  inch  apart,  are 
drawn  across  a  triangle  with  the  sides  three 
inches  in  length,  it  will  be  divided  into  three 
parts  of  equal  length.  Now  if  worms  seized 
indifferently  by  chance  any  part,  they 
would  assuredly  seize  on  the  basal   part   or 


Chap.  II.  THEIR   INTELLIGENCE.  85 

division  far  oftener  than  on  either  of  the  two 
other  divisions.  For  the  area  of  the  basal  to 
the  apical  part  is  as  5  to  1,  so  that  tlie 
chance  of  the  former  being  drawn  into  a 
burrow  by  suction,  will  be  as  5  to  1,  compared 
with  the  apical  part.  The  base  offers  two 
angles  and  the  apex  only  one,  so  that  the 
former  would  have  twice  as  good  a  chance 
(independently  of  the  size  of  the  angles)  of 
being  engulfed  in  a  worm's  mouth,  as  would 
the  apex.  It  should,  however,  be  stated  that 
the  apical  angle  is  not  often  seized  by  worms ; 
the  margin  at  a  little  distance  on  either  side 
being  preferred.  I  judge  of  this  from  having 
found  in  40  out  of  46  cases  in  which  tri- 
angles had  been  drawn  into  burrows  by  their 
apical  ends,  that  the  tip  had  been  doubled 
back  within  the  burrow  for  a  length  of 
between  ^^^th  of  an  inch  and  1  inch.  Lastly, 
the  proportion  between  the  margins  of  the  basal 
and  apical  parts  is  as  3  to  2  for  the  broad, 
and  2^  to  2  for  the  narrow  triangles.  From 
these  several  considerations  it  might  certainlv 
Lave  been  expected,  supposing  that  worms 
seized  hold  of  the  triangles  by  chance,  that  a 
consldtrably  larger    proportion   would   have 


86  HABITS   OF   WORMS.  Chap.  II. 

been  dragged  into  the  burrows  by  the  basal 
than  by  the  apical  part;  but  we  shall  im- 
mediately see  how  different  was  the  result. 

Triangles  of  the  above  specified  sizes  were 
scattered  on  the  ground  in  many  places  and 
on  many  successive  nights  near  worm-bur- 
rows, from  which  the  leaves,  petioles,  twigs, 
&c.,  with  which  they  had  been  plugged,  were 
removed.  Altogether  303  triangles  were 
drawn  by  worms  into  their  burrows  :  12  others 
were  drawn  in  by  both  ends,  but  as  it  was  im- 
possible to  judge  by  which  end  they  had  been 
first  seized,  these  are  excluded.  Of  the  303, 
62  per  cent,  had  been  drawn  in  by  the  apex 
(using  this  term  for  all  drawn  in  by  the 
apical  part,  one  inch  in  length)  ;  15  per  cent, 
by  the  middle  ;  and  23  per  cent,  by  the  basal 
part.  If  they  had  been  drawn  indifferently 
by  any  point,  the  proportion  for  the  apical, 
middle  and  basal  parts  would  have  been  33*3. 
per  cent,  for  each  ;  but,  as  we  have  just  seen, 
it  might  have  been  expected  that  a  much 
larger  proportion  would  have  been  drawn  in 
by  the  basal  than  by  any  other  part.  As  the 
case  stands,  nearly  three  times  as  many  v/ere 
drawn  in  by  tlie  apex  as  by  the  base.     If  we 


CuAP.  II.  TUEIR    INTELLIGENCE.  87 

consider  the  broad  triangles  by  themselves, 
59  per  cent,  were  drawn  in  by  the  apex,  25 
per  cent,  by  the  middle,  and  16  per  cent,  by 
the  base.  Of  the  narrow  triangles,  65  pei 
cent,  were  drawn  in  by  the  apex,  14  per  cent, 
by  the  middle,  and  21  per  cent,  by  the  base  ; 
so  that  here  those  drawn  in  by  the  apex  were 
more  than  3  times  as  many  as  those  drawn 
in  by  the  base.  We  may  therefore  conclude 
that  the  manner  in  which  the  triangles  are 
drawn  into  the  bm-rows  is  not  a  matter  of 
chance. 

In  eight  cases,  two  triangles  had  been  drawn 
into  the  same  burrow,  and  in  seven  of  these 
cases,  one  had  been  drawn  in  by  the  apex  and 
the  other  by  the  base.  This  again  indicates 
that  the  result  is  not  determined  by  chance. 
Worms  appear  sometimes  to  revolve  in  the 
act  of  drawing  in  the  triangles,  for  five  out  of 
the  whole  lot  had  been  wound  into  an  irregular 
spire  round  the  inside  of  the  burrow.  .Worms 
kept  in  a  warm  room  drew  63  triangles 
into  their  burrows ;  but,  as  in  the  case  of  the 
pine-leaves,  they  worked  in  a  rather  careless 
manner,  for  only  44  per  cent,  were  drawn  in 
by  the  apex,  22  per  cent,  by  the  middle,  and- 


88  HABITS   OF   WORMS.  Chap.  II. 

83  per  cent,  by  the  base.     In  five  cases,  two 
triangles  were  drawn  into  the  same  burrow. 

It  may  be  suggested  with  much  apparent 
probability  that  so  large  a  proportion  of  tlio 
triangles  were  drawn  in  by  the  apex,  not  from 
the  w^orms  having  selected  this  end  as  the 
most  convenient  for  the  purpose,  but  from 
having  first  tried  in  other  ways  and  failed. 
This  notion  was  countenanced  by  the  manner 
in  which  worms  in  confinement  were  seen  to 
drag  about  and  drop  the  triangles  ;  but  then 
they  were  working  carelessly.  I  did  not  at 
first  perceive  the  importance  of  this  subject^ 
but  merely  noticed  that  the  bases  of  those  tri- 
angles which  had  been  drawn  in  by  the  apex, 
were  generally  clean  and  not  crumpled.  The 
subject  was  afterwards  attended  to  carefully. 
In  the  first  place  several  triangles  which  had 
been  drawn  in  by  the  basal  angles,  or  by  the 
base,  or  a  little  above  the  base,  and  which 
were  thus  much  crumpled  and  dirtied,  were 
left  for  some  hours  in  water  and  were  then 
well  shaken  while  immersed  ;  but  neither 
the  dirt  nor  the  creases  were  thus  removed. 
Only  slight  creases  could  be  obliterated, 
even   by  pulling   the    wet   triangles   several 


CiiAP.  11.  THEIR   INTELLIGEKCE.  89 

times  throngli  my  fingers.  Owing  to  the 
slime  from  the  worms'  bodies,  the  dirt  was 
not  easily  w^ashed  off.  We  may  therefore 
conclude  that  if  a  triangle,  before  being 
dragged  in  by  the  apex,  had  been  dragged 
into  a  burrow  by  its  base  with  even  a  slight 
degree  of  force,  the  basal  part  would  long 
retain  its  creases  and  remain  dirty.  The  con- 
dition of  89  triangles  (65  narrow  and  24 
broad  ones),  which  had  been  drawn  in  by  the 
apex,  was  observed  ;  and  the  bases  of  only  7 
of  them  were  at  all  creased,  being  at  the  same 
time  generally  dirty.  Of  the  82  nncreased 
triangles,  14  were  dirty  at  the  base;  but  it 
does  not  follow  from  this  fact  that  these  had 
first  been  dragged  towards  the  burrows  by 
their  bases ;  for  the  worms  sometimes  covered 
large  portions  of  the  triangles  with  slime, 
and  these  when  dragged  by  the  apex  over  the 
ground  would  be  dirtied ;  and  during  rainy 
weather,  the  triangles  w^ere  often  dirtied  over 
one  whole  side  or  over  both  sides.  If  the 
worms  had  dragged  the  triangles  to  the 
mouths  of  their  burrows  by  their  bases,  as  often 
as  by  their  apices,  and  had  then  perceived, 
without  actually  trying  to  draw  them  into  the 


90 


HABITS   OF   WORMS. 


CiiAP.  IT. 


burrow,  that  the  broader  end  was  not  well 
adapted  for  this  purpose — even  in  this  case 
a  large  proportion  would  probably  have  had 
their  basal  ends  dirtied.  We  may  therefore 
infer — improbable  as  is  tlie  inference — that 
worms  are  able  by  some  means  to  judge 
which  is  the  best  end  by  which  to  draw 
triangles  of  paper  into  their  burrows. 

The  per  centage  results  of  the  foregoing  ob- 
servations on  the  manner  in  which  worms 
draw  various  kinds  of  objects  into  the  mouths 
of  their  burrows  may  be  abridged  as  follows  : — 


Drawn 

into  the     Dravm 

Drawn 

Nature  of  Object. 

burrows, 
by  or 

in,  by  or 

near the 

in,  by  or 

near  the 

near  the 

middle. 

base. 

apex. 

Leaves  of  various  kinds    . 

80 

11 

9 

nf  thp  Tjimp   I^'^'^al  inar^ii  ^f 

blade    broad,  apex   acumi- 

nated      .... 

79 

17 

4 

of  a  Laburnum,  basal  part  of 

blade  as  narrow  as,  or  some- 

times little   narrower   than 

the  apical  part. 

63 

10 

27 

of   the   Rhododendron,  basal 

part  of  blade  often  narrower 

than  the  apical  part  . 

34 

.. 

6« 

of  Pine-tr'^'^=    n.>n«i«tincr  nf  two 

needles  arising  from,  a  com- 

mon base 

100 

Chap.  II. 


THEIR   INTELIJGENCE. 


91 


Nature  of  Object. 


Drawn 
into  the 
burrows, 

by  or 
near  the 

Drawn 
in,  by  or: 
near  the 

middle. 

apex. 

76 

48-5 

•• 

44 

62 

15 

59 

■    25 

65 

14 

Drawn 

in,  by  ct 

near  the 

base. 


Petioles  of  a  Clematis,  somewhat 
pointed  at  the  apex,  and 
blimt  at  the  base 

of  the  Ash,  the  thick  basal 

end  often  drawn  in  to  serve 
as  food    .... 


of  Robinia,  extremely    thin, 

especially  towards  the  apex, 
so  as  to  be  ill-fitted  fur 
plugging  up  the  burrows    . 

Triangles  of  paper,  of  the  two  sizes  . 

of  the  broad  ones  alone 

• of  the  narrow  ones  alone 


24 


51-5 


56 
23 
16 
21 


If  we  consider  these  several  cases,  we  can 
Lardly  escape  from  the  conclusion  that  worms 
show  some  degree  of  intelligence  in  their 
manner  of  plugging  up  their  burrows.  Each 
particular  object  is  seized  in  too  uniform  a 
manner,  and  from  causes  which  we  can 
generally  understand,  for  the  result  to  be 
attributed  to  mere  chance.  That  every  object 
has  not  been  drawn  in  by  its  pointed  end, 
may  be  accounted  for  by  labour  having  been 
saved  through  some  being  inserted  by  their 
broader  or  thicker  ends.      No   doubt  worms 


92  HABITS   OF   WOKMS.  Chap.  II 

are  led  by  instinct  to  plug  up  their  burrows ; 
and  it  might  have  been  expected  that  they 
would  have  been  led  by  instinct  how  best- 
to  act  in  each  particular  case,  independently 
of  intelligence.  We  see  how  difficult  it  is  to 
judge  whether  intelligence  comes  into  play, 
for  even  plants  might  sometimes  be  thought 
to  be  thus  directed ;  for  instance  when  dis- 
placed leaves  re-direct  their  upper  surfaces 
towards  the  light  b}^  extremely  complicated 
movements  and  by  the  shortest  course.  With 
animals,  actions  appearing  due  to  intelligence 
may  be  performed  through  inherited  habit 
without  any  intelligence,  although  aborigin- 
ally thus  acquired.  Or  the  habit  may  have 
been  acquired  through  the  preservation  and 
inheritance  of  beneficial  variations  of  some 
other  habit ;  and  in  this  case  the  new  habit 
will  have  been  acquired  independently  of 
intelligence  throughout  the  whole  course 
of  its  development.  There  is  no  a  prion 
improbability  in  worms  having  acquired 
special  instincts  through  either  of  these  two 
latter  means.  Nevertheless  it  is  incredible 
that  instincts  should  have  been  developed 
in  reference  to  objects,  such  as  the  leaves  or 


Chap.  II.  THEIR   INTELLIGENCE.  93 

petioles  of  foreign  plants,  wholly  unknown 
to  the  progenitors  of  the  worms  which  act 
in  the  described  manner.  Nor  are  their  actions 
80  unvarying  or  inevitable  as  are  most  true 
instincts. 

As  worms  are  not  guided  by  special  in- 
stincts in  each  particular  case,  though  pos- 
sessing a  general  instinct  to  plug  up  their 
burrows,  and  as  chance  is  excluded,  the  next 
most  probable  conclusion  seems  to  be  that 
they  try  in  many  different  ways  to  draw  in 
objects,  and  at  last  succeed  in  some  one  way. 
But  it  is  surprising  that  an  animal  so  low 
in  the  scale  as  a  worm  should  have  the 
capacity  for  acting  in  this  manner,  as  many 
higher  animals  have  no  such  capacity.  For 
instance,  ants  may  be  seen  vainly  trying 
to  drag  an  object  transversely  to  their 
course,  which  could  be  easily  drawn  lougi- 
fcudinally ;  though  after  a  time  they  gener- 
ally act  in  a  wiser  mauner.  M.  Fabre 
states*  that  a  Sphex — an  insect  belong- 
ing to  the  same  highly-endowed  order 
with    ants — stocks    its    nest  with    paralysed 

*  See  his  interesting  work,  '  Souvenirs  entomologiques,'  1879, 
pp.  168-177. 


9i  HABITS   OF   WORMS.  Chap.  IL 

grasshoppers,  which  are  invariably  dragged 
into  the  burrow  by  their  antennae.  When 
these  were  cut  off  close  to  the  head,  the 
Sphex  seized  the  palpi  ;  but  when  the.se 
were  likewise  cut  off,  the  attempt  to  drag 
its  prey  into  the  burrow  was  given  up  in 
despair.  The  Sphex  had  not  intelHgence 
enough  to  seize  one  of  the  six  legs  or 
the  ovipositor  of  the  grasshopper,  which,  as 
M.  Fabre  remarks,  would  have  served  equally 
well.  So  again,  if  the  paralysed  prey  with 
an  egg  attached  to  it  be  taken  out  of  the 
cell,  the  Sphex  after  entering  and  finding  the 
cell  empty,  nevertheless  closes  it  up  in  the 
usual  elaborate  manner.  Bees  will  try  to 
escape  and  go  on  buzzing  for  hours  on  a 
window,  one  half  of  which  has  been  left  open. 
Even  a  pike  continued  during  three  months 
to  dash  and  bruise  itself  against  the  glass 
sides  of  an  aquarium,  in  the  vain  attempt  to 
seize  minnows  on  the  opposite  side.*  A  cobra- 
snake  was  seen  by  Mr.  Layard  f  to  act  much 
more  wisely  than  either  the  pike  or  the  Sphex  ; 

*  Mobius,  'Die  Bewegiingen  der  Thiere,'  &c.,  1873,  p.  111. 
t  'Annals  and  Mag.  of  N.  Uistory,'  series  ii.  vol.  ix.  1852, 
P.  333. 


CiiAP.  II.  THEIR   INTELLIGENCE.  95 

it  had  swallowed  a  toad  lying  w^ithin  a  hole, 
and  could  not  withdraw  its  head  ;  the  toad 
was  disgorged,  and  hegan  to  crawd  away;  it 
was  again  swallowed  and  again  disgorged ; 
and  now  the  snake  had  learnt  by  experience, 
for  it  seized  the  toad  by  one  of  its  legs  and 
drew^  it  out  of  the  hole.  The  instincts  of 
even  the  higher  animals  are  often  followed 
in  a  senseless  or  purposeless  manner :  the 
weaver-bird  will  perseveringly  wind  threads 
through  the  bars  of  its  cage,  as  if  building  a 
nest :  a  squirrel  will  pat  nuts  on  a  wooden 
floor,  as  if  he  had  just  buried  them  in  the 
ground  :  a  beaver  will  cut  up  logs  of  wood  and 
drag  them  about,  though  there  is  no  water  to 
dam  up  ;  and  so  in  many  other  cases. 

Mr,  Romanes  who  has  specially  studied 
the  minds  of  animals,  believes  that  we  can 
safely  infer  intelligence,  only  when  we  see  an 
individual  profiting  by  its  own  experience. 
By  this  test  the  cobra  showed  some  intelli- 
gence ;  but  this  would  have  been  much 
plainer  if  on  a  second  occasion  he  had  drawn 
a  toad  out  of  a  hole  by  its  leg.  The  Sphex 
failed  signally  in  this  respect.  Now  if 
worms  try  to  drag  objects  into  their  burrows 


96  HABITS   OF   "WORMS.  Chap.  II. 

first  in  one  way  and  then  in  another,  until 
they  at  last  succeed,  they  profit,  at  least  in 
each  particular  instance,  by  experience. 

But  evidence  has  been  advanced  showing 
t]iat  worms  do  not  habitually  try  to  draw 
objects  into  their  burrows  in  many  difierent 
ways.  Thus  half-decayed  lime-leaves  from 
their  flexibility  could  have  been  drawn  in  by 
their  middle  or  basal  parts,  and  were  thus 
drawn  into  the  burrows  in  considerable 
numbers;  yet  a  large  majority  were  drawn 
in  by  or  near  the  apex.  The  petioles  of  the 
Clematis  could  certainly  have  been  drawn  in 
with  equal  ease  by  the  base  and  apex  ;  yet 
three  times  and  in  certain  cases  five  times  as 
many  were  drawn  in  by  the  apex  as  by  the 
base.  It  might  have  been  thought  that  the 
foot-stalks  of  leaves  would  have  tempted  the 
worms  as  a  convenient  handle  ;  yet  they  are 
not  largely  used,  except  when  the  base  of  the 
blade  is  narrov/er  than  the  apex.  A  large 
number  of  the  petioles  of  the  ash  are  drawn 
in  by  the  base ;  tut  this  part  serves  the 
worms  as  food.  In  the  case  of  pine-leaves 
worms  plainly  show  that  they  at  least  do 
not    seize    the   leaf    by    chance  ;     but  their 


CnAP.  II.  THEIR   INTELLIGENCE.  97 

choice  does  not  appear  to  be  determined  by 
the  divergence  of  the  two  needles,  and  the 
consequent  advantage  or  necessity  of  drawing 
them  into  their  burrows  by  the  base.  With 
respect  to  the  triangles  of  paper,  those  which 
had  been  drawn  in  by  the  apex  rarely  had 
their  bases  creased  or  dirty ;  and  this  shows 
that  the  worms  had  not  often  first  tried  to 
drag  them  in  by  this  end. 

If  worms  are  able  to  judge,  either  before 
drawing  or  after  having  drawn  an  object 
close  to  the  mouths  of  their  burrows,  how 
best  to  drag  it  in,  they  must  acquire  some 
notion  of  its  general  shape.  This  they  pro- 
bably acquire  by  touching  it  in  many  places 
with  the  anterior  extremity  of  their  bodies, 
which  serves  as  a  tactile  organ.  It  may  be 
well  to  remember  how  perfect  the  sense  of 
touch  becomes  in  a  man  when  born  blind  and 
deaf,  as  are  worms.  If  worms  have  the 
power  of  acquiring  some  notion,  however 
rude,  of  the  shape  of  an  object  and  of  their 
burrows,  as  seems  to  be  the  case,  they  deserve 
to  be  called  intelligent ;  for  they  then  act  in 
nearly  the  same  manner  as  would  a  man 
under  similar  circumstances. 


98  HABITS   OF    vVORMS.  Cuap.  II 

To  sum  up,  as  chance  does  not  determine 
the  manner  in  which  objects  are  drawn  into 
the  burrows,  and  as  the  existence  of  special- 
ized instincts  for  each  particular  case  cannot 
be  admitted,  the  first  and  most  natural  sup- 
position is  that  worms  try  all  methods  until 
they  at  last  succeed  ;  but  many  appearances 
are  opposed  to  such  a  supposition.  One 
alternative  alone  is  left,  namely,  that  worms, 
although  standing  low  in  the  scale  of  organiz- 
ation, possess  some  degree  of  intelligence. 
This  will  strike  every  one  as  very  impro- 
bable ;  but  it  may  be  doubted  whether  we 
know  enough  about  the  nervous  system  of 
the  lower  animals  to  justify  our  natural  dis- 
trust of  such  a  conclusion.  With  respect  to 
tlie  small  size  of  the  cerebral  ganglia,  we 
should  remember '  what  a  mass  of  inherited 
knowledge,  with  some  power  of  adapting 
means  to  an  end,  is  crowded  into  the  minute 
brain  of  a  worker-ant. 

Means  by  which  worms  excavate  their 
burrows. — This  is  effected  in  two  ways ;  by 
pushing  away  the  earth  on  all  sides,  and  by 
swallowing  it.  In  the  former  ca^e,  the  worm 
inserts    the    stretched     out    and    attenuated 


Chap.  II.     EXCAVATION   OF   THEIE   BUEEOWS.      99 

anterior  extremity  of  its  body  into  any  little 
crevice,  or  hole ;  and  then,  as  Perrier  re> 
marks,*  the  pharynx  is  pushed  forwards  iiito 
this  part,  which  consequently  swells  and 
pushes  away  the  earth  on  all  sides.  The 
anterior  extremity  thus  serves  as  a  wedge. 
It  also  serves,  as  we  have  before  seen,  for 
prehension  and  suction,  and  as  a  tactile  organ. 
A  worm  was  placed  on  loose  mould,  and  it 
buried  itself  in  between  two  and  three 
minutes.  On  another  occasion  four  worms 
disappeared  in  15  minutes  between  the  sides 
of  the  pot  and  the  earth,  which  had  been 
moderately  pressed  dowu.  On  a  third  oc- 
casion three  large  worms  and  a  small  one 
were  placed  on  loose  mould  well  mixed  with 
fine  sand  and  firmly  pressed  down,  and  they 
all  disappeared,  except  the  tail  of  one,  in 
35  minutes.  On  a  fourth  occasion  six  large 
worms  were  placed  on  argillaceous  mud 
mixed  with  sand  firmly  pressed  down,  and 
they  disappeared,  except  the  extreme  tips  of 
the  tails  of  two  of  them,  in  40  minutes.  In 
none  of  these  cases,  did  the  worms  swallow, 
as  far  as  could   be    seen,  any  earth.     They 

*  '  Archives  de  Zoolog  exper.'  torn.  iii.  1874,  p.  405. 


100  HABITS   OF   WORMS.  Chap.  IL 

generally  entered  the  ground  close  to  tlie 
sides  of  the  pot. 

A  pot  was  next  filled  with  very  fine  ferru- 
ginous sand,  whicli  was  pressed  down,  well 
watered,  and  thus  rendered  extremely  com- 
pact. A  large  worm  left  on  the  surface  did 
not  succeed  in  penetrating  it  for  some  hours, 
and  did  not  bury  itself  completely  until  25 
hrs.  40  min.  had  elapsed.  This  was  effected 
by  the  sand  being  swallowed,  as  was  evident 
by  the  large  quantity  ejected  from  the  vent, 
long  before  the  whole  body  had  disappeared. 
Castings  of  a  similar  nature  continued  to  be 
ejected  from  the  burrow  during  the  whole 
of  the  following  day. 

As  doubts  have  been  expressed  by  some 
writers  whether  worms  ever  swallow  earth 
solely  for  the  sake  of  making  their  burrows, 
some  additional  cases  may  be  given.  A  mas? 
of  fine  reddish  sand,  23  inches  in  thickness, 
left  on  the  ground  for  nearly  two  years, 
had  been  penetrated  in  many  places  by 
worms  ;  and  their  castings  consisted  partly  ot 
the  reddish  sand  and  partly  of  black  earth 
brought  up  from  beneath  the  mass.  This 
sand    had  been  dug  up  from  a  considerable 


Ch.ap.  TI.    excavation    OF   THEIR   BUEEOWS.     101 

depth,  and  was  of  so  poor  a  nature  that 
weeds  could  not  grow  on  it.  It  is  therefore 
highly  improbable  that  it  should  have  been 
swallowed  by  the  worms  as  food.  Again  ia 
a  field  near  my  liouse  the  castings  frequently 
consist  of  almost  pure  chalk,  which  lies  at  only 
a  little  depth  beneath  the  surface  ;  and  here 
again  it  is  very  improbable  that  the  chalk 
should  have  been  swallowed  for  the  sake  of 
the  very  little  organic  matter  which  could 
have  percolated  into  it  from  the  poor  over- 
lying pasture.  Lastly,  a  casting  thrown  up 
through  the  concrete  and  decayed  mortar 
between  the  tiles,  with  which  the  now  ruined 
aisle  of  Beaulieu  Abbey  had  formerly  been 
paved,  was  washed,  so  that  the  coarser 
matter  alone  was  left.  This  consisted  of 
grains  of  quartz,  micaceous  slate,  other  rocks, 
and  bricks  or  tiles,  many  of  them  from  -^^  to 
■jL  inch  in  diameter.  No  one  will  suppose 
that  these  grains  were  swallowed  as  food,  yet 
they  formed  more  than  half  of  the  casting, 
for  they  weighed  19  grains,  the  whole  cast- 
ing having  weighed  33  grains.  Whenever  a 
worm  burrows  to  a  depth  of  some  feet  in 
undisturbed  compact  ground,  it  must  form  its 


L02  HABITS   OF   WOllMS.  Chap.  U 

passage  by  swallowing  the  earth  ;  for  it  is 
incredible  that  the  ground  could  yield  on  all 
sides  to  the  pressure  of  the  pharynx  when 
pushed  forwards  within  the  worm's  body. 

That  worms  swallow  a  larger  quantity  of 
earth  for  the  sake  of  extracting  any  nutritious 
matter  which  it  may  contain  than  for  making 
their  burrows,  appears  to  me  certain.  But 
as  this  old  belief  has  been  doubted  by  so  high 
an  authority  as  Claparede,  evidence  in  its 
favour  must  be  given  in  some  detail.  There 
is  no  a  priori  improbability  in  such  a  belief, 
for  besides  other  annelids,  especially  the 
Arenicola  marina,  which  throws  up  such  a 
profusion  of  castings  on  our  tidal  sands,  and 
which  it  is  believed  thus  subsists,  tliere  ;ire 
animals  belonging  to  the  most  distinct  classes, 
which  do  not  burrow,  but  habitually  swallow 
large  quantities  of  sand ;  namely  the  mollus- 
can  Oncliidium  and  many  Echinoderms.* 

If  earth  were  swallowed  only  when  worms 
deepened  their  burrow^s  or  made  new  ones, 
castings  would  be  thrown  up  only  occasion- 
ally ;  but  in  many  places  fresh  castings  may 

*  I   state   this  on   the  authority   of    Semper,    'Eeisen   im 
Archii>l  der  rhilippinen,"  Th.  ii.  1877,  p.  30. 


Chap.  IT.      EARTH   SWALLOWED   AS   FOOD.  103 

be  seen  every  morning,  and  the  amount 
of  earth  ejected  from  the  same  burrow  on 
successive  days  is  large.  Yet  worms  do  not 
burrow  to  a  great  depth,  except  when  tlie 
weather  is  very  dry  or  intensely  cold.  On 
my  lawn  the  black  vegetable  mould  is  only 
about  5  inches  in  thickness,  and  overlies  light- 
coloured  or  reddish  clayey  soil:  now  when 
castings  are  thrown  up  in  the  greatest 
profusion,  only  a  small  proportion  are  light 
coloured,  and  it  is  incredible  that  the  worms 
should  daily  make  fresh  burrows  in  every 
direction  in  the  thin  superficial  layer  of 
dark -coloured  humus,  unless  they  obtained 
nutriment  of  some  kind  from  it.  I  have 
observed  a  strictly  analogous  case  in  a  field  near 
my  house  where  bright  red  clay  lay  close 
beneath  the  surface.  Again  on  one  part  of 
the  Downs  near  Winchester  the  vegetable 
mould  overlying  the  chalk  was  found  to  be 
only  from  3  to  4  inches  in  thickness ;  and  the 
many  castings  here  ejected  were  as  black  as 
ink  and  did  not  effervesce  with  acids  ;  so  that 
the  worms  must  have  confined  themselves  to 
this  thin  superficial  layer  of  mould,  of  which 
large    quantities   were    daily  swallowed.     In 


i04  HABITS   OF   WORMS.  Cuap.  II. 

another  place  at  no  great  distance  the 
castings  were  white  ;  and  why  the  worms 
should  have  burrowed  into  the  chalk  in  some 
places  and  not  in  others,  I  am  unable  to 
conjecture. 

Two  great  piles  of  leaves  had  been  left  to 
decay  in  my  grounds,  and  months  after  their 
removal,  the  bare  surface,  several  yards  in 
diameter,  was  so  thickly  covered  during 
several  months  with  castings  that  they  formed 
an  almost  continuous  layer ;  and  the  large 
number  of  worms  which  lived  here  must  have 
subsisted  during  these  months  on  nutritious 
matter  contained  in  the  black  earth. 

The  lowest  layer  from  another  pile  of  de- 
cayed leaves  mixed  with  some  earth  was  ex- 
amined under  a  high  power,  and  the  number 
of  spores  of  various  shapes  and  sizes  which 
it  contained  was  astonishingly  great ;  and 
these  crushed  in  the  gizzards  of  worms  may 
largely  aid  in  supporting  them.  When- 
ever castings  are  thrown  up  in  the  greatest 
number,  few  or  no  leaves  are  drawn  into  the 
burrows ;  for  instance  the  turf  along  a  hedge- 
row, about  200  yards  in  length,  was  daily 
observed  in  the  autumn  during  several  weeks, 


Chap.  II.      EARTH   SWALLOWED   AS   FOOD.  105 

and  every  morning  many  fresli  castings  were 
seen  ;  but  not  a  single  leaf  was  drawn  into  these 
burrows.  These  castings  from  their  blackness 
and  from  the  nature  of  the  subsoil  could  not 
have  been  brought  up  from  a  greater  depth 
than  6  or  8  inches.  On  what  could  these 
worms  have  subsisted  during  this  whole  time, 
if  not  on  matter  contained  in  the  black  earth  ? 
On  the  other  hand,  whenever  a  large  number 
of  leaves  are  drawn  into  the  burrows,  the 
worms  seem  to  subsist  chiefly  on  them,  for 
few  earth-castings  are  then  ejected  on  the 
surface.  This  difference  in  the  behaviour  of 
worms  at  different  times,  perhaps  explains  a 
statement  by  Claparede,  namely,  that  triturated 
leaves  and  earth  are  always  found  in  distinct 
parts  of  their  intestines. 

Worms  sometimes  abound  in  places  where 
they  can  rarely  or  never  obtain  dead  or 
living  leaves ;  for  instance,  beneath  the  pave- 
ment in  well-swept  courtyards,  into  which 
leaves  are  only  occasionally  blown.  My  son 
Horace  examined  a  house,  one  corner  of 
which  had  subsided;  and  he  found  here  in 
the  cellar,  which  was  extremely  damp,  many 
small  worm-castings  thrown  up  between  the 


106  HABITS   OF   WORMS.  Chap.  IL 

stones  witli  which  the  cellar  was  paved  ;  and 
in  this  case  it  is  improbable  that  the  worms 
could  ever  have  obtained  leaves. 

But  the  best  evidence,  known  to  me,  of 
worms  subsisting  for  at  least  considerable 
periods  of  time  solely  on  the  organic  matter 
contained  in  earth,  is  afforded  by  some  facts 
communicated  to  me  by  Dr.  King.  Near 
Nice  large  castings  abound  in  extraordinary 
numbers,  so  that  5  or  6  were  often  found 
within  the  space  of  a  square  foot.  They 
consist  of  fine,  pale-coloured  earth,  containing 
calcareous  matter,  which  after  having  passed 
through  the  bodies  of  worms  and  being  dried, 
coheres  with  considerable  force.  I  have 
reason  to  believe  that  these  castings  had  been 
formed  by  species  of  Perichaata,  which  have 
been  naturalised  here  from  the  East.*     Thev 

*  Dr.  King  gave  me  some  worms  collected  near  Nice,  whicli, 
as  he  "believes,  had  constructed  these  castings.  They  were  sent 
to  M.  Perrier,  who  with  great  kindness  examiaed  and  named  them 
for  me:  they  consisted  of  Ferichceta  affinis,  a  native  of  Cochin 
China  and  of  the  Philippines  ;  P.  Luzonica,  a  native  of  Luzon 
in  the  Philippines  ;  and  P.  HouUeti,  which  lives  near  Calciitta. 
M.  Perrier  informs  me  that  species  of  Perichaata  have  been  natural- 
ized in  the  gardens  near  Montpellier  and  in  Algiers.  Before  I 
had  any  reason  to  suspect  that  the  tower-like  castings  from  Nice 
had  been  formed  by  worm?  not  endemic  in  the  country,  I  waa 


Chap.  II.      EAETH   SWALLOWED   AS   FOOD. 


107 


rise  like  towers  (see  Fig.  2),  with  their  sum- 
inits  often  a  httle  hroader  than  their  bases, 


Fig.  2. 

Towfer-Iike  casting  from  near  Nice,  constructed  of  earth,  voided 
prooably  by  a  species  of  Pericliseta  :  of  natural  size,  copied  from 
a  photograph. 


sometimes  to  a  height  of  above  3  and  often 
to  a  height  of  2  J  inches.     The  tallest  of  those 


greatly  surprised  to  see  how  closely  they  resembled  castings  sent 
to  me  from  near  Calcutta,  where  it  is  known  that  species  of 
Perich£eta  abound. 


108  HABITS   OF   WORMS.  Chap.  II. 

whicli  were  measured  was  3*3  inch  in  height 
and  1  in  diameter.  A  small  cylindrical  pas- 
sage runs  up  the  centre  of  each  tower, 
through  which  the  worm  ascends  to  eject  the 
earth  which  it  has  swallowed,  and  thus  to 
add  to  its  height.  A.  structure  of  this  kind 
would  not  allow  leaves  being  easily  dragged 
from  the  surrounding  ground  into  the  bur- 
rows ;  and  Dr.  King,  who  looked  carefully, 
never  saw  even  a  fragment  of  a  leaf  thus 
drawn  in.  Nor  could  any  trace  be  discovered 
of  the  worms  having  crawled  down  the  ex- 
terior surfaces  of  the  towers  in  search  of 
leaves;  and  had  they  done  so,  tracks  would 
almost  certainly  have  been  left  on  the  upper 
part  whilst  it  remained  soft.  It  does  not, 
however,  follow  that  these  worms  do  not 
draw  leaves  into  their  burrows  during  some 
other  season  of  the  year,  at  which  time  they 
would  not  build  up  their  towers. 

From  the  several  foregoing  cases,  it  can 
hardly  be  doubted  that  worms  swallow  earth, 
not  only  for  the  sake  of  making  their  bur- 
rows, but  for  obtaining  food.  Hensen,  how- 
ever, concludes  from  his  analyses  of  humus 
that    worms    probably    could    not    live    on 


Chap.  U.      DEPTH   OF   THEIK   BURROWS.  109 

ordinary  vegetable  mould,  though  he  admits 
that  they  might  be  nourished  to  some  extent 
by  leaf-mould.*  But  we  have  seen  that 
worms  eagerly  devour  raw  meat,  fat,  and 
dead  worms  ;  and  ordinary  mould  can  hardly 
fail  to  contain  many  ova^  larvae,  and  small 
living  or  dead  creatures,  spores  of  crypto- 
gamic  plants,  and  micrococci,  such  as  those 
which  give  rise  to  saltpetre.  These  various 
organisms,  together  with  some  cellulose  from 
any  leaves  and  roots  not  utterly  decayed, 
might  well  account  for  such  large  quantities 
of  mould  being  swallowed  by  worms.  It 
may  be  worth  while  here  to  recall  the  fact 
that  certain  species  of  Utricularia,  which  grow 
in  damp  places  in  the  tropics,  possess  bladders 
beautifully  constructed  for  catching  minute 
subterranean  animals  ;  and  these  traps  would 
not  have  been  developed  unless  many  small 
animals  inhabited  such  soil. 

The  depth  to  which  worms  penetrate^  and 
the  construction  of  their  burrows.  —  Although 
worms  usually  live  near  the  surface,  yet  they 
burrow  to  a  considerable  depth  during  long- 

*  *  Zeitsclirift    fiii-    wissenscliaft.    Zoolog.'    B.   xxviii.   1877 
p.  3G4. 


110  HABITS   OF   WOEMS.  Chap.  II. 

continued  dry  weather  and  severe  cold.  In 
Scandinavia,  according  to  Eisen,  and  in  Scot- 
land, according  to  Mr.  Lindsay  Carnagie,  the 
burrows  run  down  to  a  depth  of  from  7  to  8 
feet ;  in  North  Germany,  according  to  Hoff- 
meister,  from  6  to  8  feet,  but  Hensen  says, 
from  3  to  6  feet.  This  latter  observer  has  seen 
worms  frozen  at  a  depth  of  1^  feet  beneath 
the  surface.  I  have  not  myself  had  many 
opportunities  for  observation,  but  I  have  often 
met  v/ith  worms  at  depths  of  3  to  4  feet. 
In  a  bed  of  fine  sand  overlying  the  chalk, 
which  had  never  been  disturbed,  a  worm  was 
cut  into  two  at  55  inches,  and  another  was 
found  here  in  December  at  the  bottom  of  its 
burrow,  at  61  inches  beneath  the  surface. 
Lastly,  in  earth  near  an  old  Eoman  Yilla, 
which  had  not  been  disturbed  for  many 
centuries,  a  worm  w^as  met  with  at  a  depth 
of  66  inches ;  and  this  was  in  the  middle  of 
August. 

The  burrows  run  down  perjoendicularly,  or 
more  commonly  a  little  obhquely.  They  are 
said  sometimes  to  branch,  but  as  far  as  I  have 
seen  this  does  not  occur,  except  in  recently 
dug  ground  and  near  the  surface.     They  are 


Chap.  II.   CONSTRUCTION  OF  THEIR  BURROWS.    Ill 

generally,  or  as  I  believe  invariably,  lined 
with  a  thin  layer  of  fine,  dark-coloured  earth 
voided  by  the  worms ;  so  that  they  must 
dt  first  be  made  a  little  wider  than  their 
ultimate  diameter.  I  have  seen  several 
burrows  in  undisturbed  sand  thus  lined  at 
a  depth  of  4  ft.  6  in. ;  and  others  close 
to  the  surface  thus  lined  in  recently  dug 
ground.  The  walls  of  fresh  burrows  are 
often  dotted  with  httle  globular  pellets  of 
voided  earth,  still  soft  and  viscid ;  and  these, 
as  it  appears,  are  spread  out  on  all  sides  by 
the  worm  as  it  travels  up  or  down  its  burrow. 
The  lining  thus  formed  becomes  very  com 
pact  and  smooth  when  nearly  dry,  and 
closely  fits  the  worm's  body.  The  minute 
reflexed  bristles  which  project  in  rows  on 
all  sides  from  the  body,  thus  have  excellent 
points  of  support ;  and  the  burrow  is  rendered 
w^ell  adapted  for  the  rapid  movement  of  the 
animal.  The  lining  appears  also  to  strengthen 
the  walls,  and  perhaps  saves  the  worm's  body 
from  being  scratched.  I  think  so  because 
several  burrows  which  passed  through  a  layer 
of  sifted  coal-cinders,  spread  over  turf  to  a 
thickness  of  1^  inch,  had  been  thus  lined  to  an 


112  HABITS   OF   WORMS.  Chap.  II 

unusual  thickness.  In  tliis  case  the  worms, 
judging  from  the  castings,  had  pushed  the 
cinders  away  on  all  sides  and  had  not 
swallowed  any  of  them.  In  another  place, 
burrows  similarly  lined,  passed  through  a 
layer  of  coarse  coal-cinders,  3^  inches  in 
thickness.  We  thus  see  that  the  burrows  are 
not  mere  excavations,  but  may  rather  be 
compared  with  tunnels  lined  with  cement. 

The  mouths  of  the  burrow  are  in  addition 
often  lined  with  leaves  ;  and  this  is  an  instinct 
distinct  from  that  of  plugging  them  up,  and 
does  not  appear  to  have  been  hitherto  noticed. 
Many  leaves  of  the  Scotch-fir  or  pine  {Pinus 
sylvestris)  were  given  to  worms  kept  in  con- 
finement in  two  pots  ;  and  when  after  several 
weeks  the  earth  was  carefully  broken  up,  the 
upper  parts  of  three  oblique  burrows  were 
found  surrounded  for  lengths  of  7,  4,  and 
3^  inches  with  pine-leaves,  together  with 
fragments  of  other  leaves  which  had  been 
given  the  worms  as  food.  Glass  beads  and 
bits  of  tile,  which  had  been  strewed  on  the 
surface  of  the  soil,  were  stuck  into  the  inter- 
stices between  the  pine-leaves ;  and  these 
interstices  were  likewise  plastered   with  the 


Chap.  II.  CONSTEUCTION   OF   THEIR   BUEROWS.  113 

viscid  castings  voided  by  the  worms.  The 
structures  thus  formed  cohered  so  well,  that  I 
succeeded  in  removing  one  with  only  a  little 
earth  adhering  to  it.  It  consisted  of  a  sli  ghtly 
curved  cylindrical  case,  the  interior  of  which 
could  be  seen  through  holes  in  the  sides  and 
at  either  end.  The  pine-leaves  had  all  been 
drawn  in  by  their  bases;  and  the  sharp  points 
of  the  needles  had  been  pressed  into  the 
lining  of  voided  earth.  Had  this  not  been 
effectually  done,  the  sharp  points  would  have 
prevented  the  retreat  of  the  worms  into  Their 
burrows ;  and  these  structures  would  have 
resembled  traps  armed  with  converging 
points  of  wire,  rendering  the  ingress  of  an 
animal  easy  and  its  egress  difiScult  or  im- 
possible. The  skill  shown  by  these  worms 
is  noteworthy  and  is  the  more  remarkable,  as 
the  Scotch  pine  is  not  a  native  of  this  district 
After  having  examined  these  burrows 
made  by  worms  in  confinement,  I  looked  at 
those  in  a  flower-bed  near  some  Scotch  pines. 
These  had  all  been  plugged  up  in  the  ordinary 
manner  with  the  leaves  of  this  tree,  drawn  in 
for  a  length  of  from  1  to  1|  inch;  but  the 
mouths  of  many  of  them  were  likewise  lined 


L14  HABITS   OF   WOEMS.  Chap.  11 

with  tliem,  mingled  with  fragments  of  other 
kinds  of  leaves,  drawn  in  to  a  depth  of  4  or  5 
inches.  Worms  often  remain,  as  formeilj 
stated^  for  a  long  time  close  to  the  mouthg 
of  their  burrows,  apparently  for  warmth ; 
and  the  basket-like  structures  formed  of 
leaves  w^ould  keep  their  bodies  from  coming 
into  close  contact  with  the  cold  damp  earth. 
That  they  habitually  rested  on  the  pine-leaves, 
was  rendered  probable  by  their  clean  and 
almost  polished  surfaces. 

The  burrows  which  run  far  down  into  the 
ground,  generally,  or  at  least  often,  terminate 
in  a  little  enlargement  or  chamber.  Here,  ac- 
cording to  Hoffmeister,  one  or  several  worms 
pass  the  winter  rolled  up  into  a  ball.  Mr. 
Lindsay  Carnagie  informed  me  (1838)  that 
he  had  examined  many  burrows  over  a  stone- 
quarry  in  Scotland,  where  the  overlying 
boulder-clay  and  mould  had  recently  been 
cleared  away,  and  a  little  vertical  cliff  thus 
left.  In  several  cases  the  same  burrow  was  a 
little  enlarged  at  two  or  three  points  one 
beneath  the  other  ;  and  all  the  burrows  ter- 
minated in  a  rather  large  chamber,  at  a  depth 
of  7  or  8  feet  from  the  surface.      These  cham- 


Chap.  II.    CONSTRUCTION  OF  THEIR  BURROWS.    115 

bers  contained  many  small  sharp  bits  of  ston^ 
and  husks  of  flax-seeds.  They  must  also 
have  contained  living  seeds,  for  on  the  follow- 
ing spring  Mr.  Carnagie  saw  grass-plants 
sprouting  out  of  some  of  the  intersected 
chambers.  I  found  at  Abinger  in  Surrey 
two  burrows  terminating  in  similar  chambers 
at  a  depth  of  36  and  41  inches,  and  these 
were  lined  or  paved  with  little  pebbles, 
about  as  large  as  mustard  seeds ;  and  in 
one  of  the  chambers  there  was  a  decayed 
oat-grain,  with  its  husk.  Hensen  likewise 
states  that  the  bottoms  of  the  burrows  are 
lined  with  little  stones ;  and  where  these 
could  not  be  procured,  seeds,  apparently  of 
the  pear,  had  been  used,  as  many  as  fifteen 
having  been  carried  down  into  a  single 
burrow,  one  of  which  had  germinated.*  We 
thus  see  how  easily  a  botanist  might  be 
deceived  who  wished  to  learn  how  long 
deeply  buried  seeds  remained  alive,  if  he 
were  to  collect  earth  from  a  considerable 
depth,  on  the  supposition  tliat  it  could 
contain  only  seeds  which  had  long  lain 
buried.      It  is  probable  that  the  little  stones, 

*  '  Zeitsclirift  fiir  wissenschaft.  Zoolosr.'  B.  xxviii.  1877,  p.  350, 


116  HABITS   OF   WOKMS.  Chap.  II. 

as  well  as  the  seeds,  are  carried  down  from 
the  surface  by  being  swallowed  ;  for  a  sur- 
prising number  of  glass  beads,  bits  of  tile 
and  of  glass  were  certainly  thus  carried  down 
by  worms  kept  in  pots ;  but  some  may  have 
been  carried  down  within  their  mouths.  The 
sole  conjecture  which  I  can  form  why  worms 
line  their  winter- quarters  with  little  stones 
and  seeds,  is  to  prevent  their  closely  coiled-up 
bodies  from  coming  into  close  contact  with 
the  surrounding  cold  soil ;  and  such  contact 
would  perhaps  interfere  with  their  respiration 
which  is  effected  by  the  skin  alone. 

A  worm  after  swallowing  earth,  whether 
for  making  its  burrow  or  for  food,  soon  comes 
to  the  surface  to  empty  its  body.  The  ejected 
earth  is  thoroughly  mingled  with  the  intestinal 
secretions,  and  is  thus  rendered  viscid.  After 
being  dried  it  sets  hard.  I  have  watched 
worms  during  the  act  of  ejection^  and  when 
the  earth  was  in  a  very  liquid  state  it  was 
ejected  in  little  spurts,  and  when  not  so 
liquid  by  a  slow  peristaltic  movement.  It  is 
not  cast  indifferently  on  any  side,  but  with 
some  care,  first  on  one  and  then  on  another 
feide ;  the  tail  being  used  almost  like  a  troweb 


Chap.  II.      EJECTION   OF   THEIR  CASTINGS.         117 

As  soon  as  a  little  heap  is  formed,  the 
worm  apparently  avoids,  for  the  sake  of 
safety,  protruding  its  tail ;  and  the  earthy 
matter  is  forced  up  through  the  previously 
deposited  soft  mass.  The  mouth  of  the  same 
burrow  is  used  for  this  purpose  for  a  consider- 
able time.  In  the  case  of  the  tower-hke 
castings  (see  Fig.  2)  near  Nice,  and  of  the 
similar  but  still  taller  towers  from  Bengal 
(hereafter  to  be  described  and  figured)  a 
considerable  degree  of  skill  is  exhibited  in 
their  construction.  Dr.  King  also  observed 
that  the  passage  up  these  towers  hardly  ever 
ran  in  the  same  exact  line  with  the  under- 
lying burrow,  so  that  a  thin  cylindrical  object 
such  as  a  haulm  of  grass,  could  not  be 
passed  down  the  tower  into  the  burrow ;  and 
this  change  of  direction  probably  serves  in 
some  manner  as  a  protection.  When  a  worm 
comes  to  the  surface  to  eject  earth,  the  tail 
protrudes,  but  when  it  collects  leaves  its  head 
must  protrude.  Worms  therefore  must  have 
the  power  of  turning  round  in  their  closely- 
fitting  burrows ;  and  this,  as  it  appears  to  us, 
would  be  a  difficult  feat. 

Worms  do  not  always  eject  their  castings  on 


118  HABITS   OF   WORMS.  Chap.  II. 

the  surface  of  the  ground.  When  they  can 
find  any  cavity,  aKS  when  burrowing  in  newly 
turned-up  earth,  or  between  the  stems  of 
banked-up  plants,  they  deposit  their  castings 
in  such  places.  So  again  any  hollow  beneath 
a  large  stone  lying  on  the  surface  of  the 
ground,  is  soon  filled  up  with  their  castings. 
According  to  Hensen,  old  burrows  are  habitu- 
ally used  for  this  purpose ;  but  as  far  as  my 
experience  serves,  this  is  not  the  case,  except- 
ing with  those  near  the  surface  in  recently  dug 
ground.  I  think  that  Hensen  may  have  been 
deceived  by  the  walls  of  old  burrows,  lined 
with  black  earth,  having  sunk  in  or  collapsed  ; 
for  black  streaks  are  thus  left,  and  these  are 
conspicuous  when  passing  through  light- 
coloured  soil,  and  might  be  mistaken  for 
completely  filled-up  burrows. 

It  is  certain  that  old  burrows  collapse  in 
the  course  of  time ;  for  as  we  shall  see  in  the 
next  chapter,  the  fine  earth  voided  by  worms, 
if  spread  out  uniformly,  would  form  in  many 
})]aces  in  the  course  of  a  year  a  layer  -^  of  an 
inch  in  thickness;  so  that  at  any  rate  this  large 
amount  is  not  deposited  within  the  old  unused 
burrows.      If  the  burrows  did  not  collapse^ 


CuAP.  11.      THE  COLLAPSE  OF  OLD  BURROWS.      119 

the  whole  ground  would  be  first  thickly 
riddled  with  holes  to  a  depth  of  about  tea 
inches,  and  in  fifty  years  a  hollow  unsu}> 
ported  space,  ten  inches  in  depth,  would  be 
left.  The  holes  left  by  the  decay  of  succes- 
sively formed  roots  of  trees  and  plants  must 
likewise  collapse  in  the  course  of  time. 

The  burrows  of  worms  run  down  perpen- 
dicularly or  a  little  obliquely,  and  where  the 
soil  is  at  all  argillaceous,  there  is  no  difficulty 
in  believing  that  the  walls  would  slowly  flow 
or  slide  inwards  during  very  wet  weather. 
When,  however,  the  soil  is  sandy  or 
mingled  with  many  small  stones,  it  can 
hardly  be  viscous  enough  to  flow  inwards 
during  even  the  wettest  weather;  but  another 
agency  may  here  come  into  play.  After 
much  rain  the  ground  swells,  and  as  it  cannot 
expand  latei-ally,  the  surface  rises ;  durmg 
dry  weather  it  sinks  again.  For  instance,  a 
large  flat  stone  laid  on  the  surface  of  a  field 
sank  3*33  mm.  whilst  the  weather  was  dry 
between  May  9th  and  June  13th,  and  rose 
1'91  mm.  between  September  7th  and  19th, 
much  rain  having  fallen  during  the  latter 
part  of  this  time.     During  frosts  and  thaws 


120  HABITS   OF   WOEMS.  Guap.  II. 

the  movements  were  twice  as  great.  These 
observations  were  made  by  my  son  Horace, 
who  will  hereafter  publish  an  acco^mt  of  the 
movements  of  this  stone  during  successive 
wet  and  dry  seasons,  and  of  the  effects  of  its 
being  undermined  by  worms.  Now  when 
the  ground  swells,  if  it  be  penetrated  by 
cylindrical  holes,  such  as  worm-burrows, 
their  walls  will  tend  to  yield  and  be  pressed 
inwards ;  and  the  yielding  will  be  greater 
in  the  deeper  parts  (supposing  the  whole 
to  be  equally  moistened)  from  the  greater 
weight  of  the  superincumbent  soil  which  has 
to  be  raised,  than  in  the  parts  near  the  sur- 
face. When  the  ground  dries,  the  walls  will 
shrink  a  little  and  the  burrows  will  be  a 
litl  le  enlarged.  Their  enlargement,  however, 
thiough  the  lateral  contraction  of  the 
ground,  will  not  be  favoured,  but  rather  op- 
posed, by  the  weight  of  the  superincumbent 
soil. 

Distribution  of  Worms. — Earth-worms  are 
found  in  all  parts  of  the  world,  and  some  of 
the  genera  have  an  enormous  range.*  They 
inhabit     the     most    isolated    islands ;     they 

•  Perrier,  '  Archives  de  Zoolog.  exp^r.'  torn.  3,  p.  378,  1874. 


Chap.  11.        THEIR    WIDE    DISTllIBUTJON.  121 

abound  in  Iceland,  and  are  known  to  exist 
in  the  West  Indies,  St.  Helena,  Madagascar, 
New  Caledonia  and  Tahiti.  In  the  Antarctic 
regions,  worms  from  Kerguelen  Land  have 
been  described  by  Ray  Lankester;  and  I 
found  them  in  the  Falkland  Islands.  How 
they  reach  such  isolated  islands  is  at  present 
quite  unknown.  They  are  easily  killed  by 
salt-water,  and  it  does  not  appear  probable 
that  young  worms  or  their  egg-capsules  could 
be  carried  in  earth  adhering  to  the  feet  or 
beaks  of  land-birds.  Moreover  Kerguelen 
Land  is  not  now  inhabited  by  any  land-bird. 

In  this  volume  we  are  chiefly  concerned  with 
the  earth  cast  up  by  worms,  and  I  have  gleaned 
a  few  facts  on  this  subject  with  respect  to 
distant  lands.  Worms  throw  up  plenty  of 
castings  in  the  United  States.  In  Yenezuela, 
castings,  probably  ejected  by  species  of 
Urochseta,  are  common  in  the  gardens  and 
fields,  but  not  in  the  forests,  as  I  hear  from 
Dr.  Ernst  of  Caracas.  He  collected  156 
castings  from  the  court-yard  of  his  house, 
having  an  area  of  200  square  yards.  They 
varied  in  bulk  from  half  a  cubic  centimeter  to 
five  cubic  centimeters,  and  were  on  an  average 


122  HABITS   OF   WORMS.  Chap.  1.1 

three  cubic  centimeters.  They  were,  therefore 
of  small  size  in  comparison  with  those  often 
found  in  Enghmd  ;  for  six  large  castings  from 
a  field  near  my  house  averaged  16  cubic  centi- 
meters. Several  species  of  earth-worms  are 
common  in  St.  Catharina  in  South  Brazil,  and 
Fritz  Muller  informs  me  "  that  in  most  parts  of 
"  the  forests  and  pasture-lands,  the  whole  soil, 
''  to  a  depth  of  a  quarter  of  a  metre,  looks  as  if  it 
"had  passed  repeatedly  through  the  intestines 
"  of  earth-worms,  even  where  hardly  any  cast- 
"  ings  are  to  be  seen  on  the  surface."  A 
gigantic  but  very  rare  species  is  found  tbere, 
the  burrows  of  which  are  sometimes  even  two 
centimeters  or  nearly  -J  of  an  inch  in  diameter, 
and  which  apparently  penetrate  the  ground 
to  a  great  depth. 

In  the  dry  climate  of  New  South  Wales,  I 
hardly  expected  that  worms  would  be  com- 
mon ;  but  Dr.  G.  Krefft  of  Sydney,  to  whom 
I  applied,  after  making  enquiries  from 
gardeners  and  others,  and  from  his  own 
observations,  informs  me  that  their  castings 
abound.  He  sent  me  some  collected  after 
heavy  rain,  and  they  consisted  of  little  pellets, 
about  '15  inch  in  diameter  ;  and  the  blackened 


Chap.  IJ.  THEIR   WIDE   DISTRIBUTION.  123 

sandy  earth  of  which  they  were  formed  still 
cohered  with  considerable  tenacity. 

The  late  Mr.  John  Scott  of  the  Botanic 
Gardens  near  Calcutta  made  many  observa* 
tions  for  me  on  worms  living  under  the  hot 
and  humid  climate  of  Bengal.  The  castings 
abound  almost  everywhere,  in  jungles  and  in 
the  open  ground,  to  a  greater  degree,  as  he 
thinks,  than  in  England.  After  the  water 
has  subsided  from  the  flooded  rice-fields,  the 
whole  surface  very  soon  becomes  studded  with 
castings — a  fact  which  much  surprised  Mr. 
Scott,  as  he  did  not  know  how  long  worms 
could  survive  beneath  water.  They  cause 
much  trouble  in  the  Botanic  garden,  "for 
"  some  of  the  finest  of  our  lawns  can  be  kept 
*'  in  anything  like  order  only  by  being  almost 
''  daily  rolled  ;  if  left  undisturbed  for  a  few  days 
**  they  become  studded  with  large  castings." 
These  closely  resemble  those  described  as 
abounding  near  Nice  ;  and  they  are  probably 
fche  work  of ,  a  species  of  Perichseta.  They 
stand  up  like  towers,  with  an  open  passage  in 
the  centre. 

A  figure  of  one  of  these  castings  from  a 
photograph    is   here    given    (Fig.    3).      The 


124 


HABITS   OF   WOKMS. 


Chap.  II. 


largest   received   by    me   was    3|    inches   in 
height  and   1-35  inch   in  diameter;  another 


Fig.  3. 

A  tower-like  casting,  probably  ejected  by  a  species  of  Perichgeta, 
from  the  Botanic  Garden,  Calcutta  :  of  natural  size,  engraved 
from  a  photograph. 

was  only  |  inch  in  diameter  and  2|  in  height. 


Cdap.  II.  THEIR   WIDE   DISTRIBUTION.  125 

In  the  following  year,  Mr.  Scott  measured 
several  of  the  largest ;  one  was  0  inches  in 
height  and  nearly  1^  in  diameter  :  two  others 
were  5  inches  in  height  and  respectively  2 
and  rather  more  than  2^  inches  in  diameter 
The  average  weight  of  the  22  castings  sent  to 
me  was  35  grammes  (li  oz.)  ;  and  one  of  them 
weighed  44*8  grammes  (or  2  oz.).  All  these 
eastings  were  thrown  up  either  in  one  night 
or  in  two.  Where  the  ground  in  Bengal  is 
dry,  as  under  large  trees,  castings  of  a  different 
kind  are  found  in  vast  numbers :  these  con- 
sist of  little  oval  or  conical  bodies,  from  about 
the  2V  ^^  rather  above  -^^  of  an  inch  in 
length.  They  are  obviously  voided  by  a 
distinct  species  of  worms. 

The  period  during  which  worms  neai 
Calcutta  display  such  extraordinary  activity 
lasts  for  only  a  little  over  two  months 
namely,  during  the  cool  season  after  the  rains. 
At  this  time  they  are  generally  found  within 
about  10  inches  beneath  the  surface.  Dunn<j 
the  hot  season  they  burrow  to  a  greater  depth, 
and  are  then  found  coiled  up  and  apparently 
hybernating.  Mr.  Scott  has  never  seen  them 
at  a  greater  depth  than  2^  feet,  but  has  heard 


J2G  HABITS   OF   WORMS.  Cii\p.  11 

of  their  liavii)g  been  found  at  4  feet.  Within 
the  forests,  fresh  castings  may  be  found  even 
during  the  hot  season.  The  worms  in  the 
Botanic  garden,  during  the  cool  and  dij 
season,  draw  many  leaves  and  little  sticka 
into  the  mouths  of  their  burrows,  like  our 
English  worms;  but  they  rarely  act  in  this 
manner  during  the  rainy  season. 

Mr.  Scott  saw  worm-castings  on  the  lofty 
mountains  of  Sikkim  in  North  India.  In 
South  India  Dr.  King  found  in  one 
j)lace,  on  the  plateau  of  the  Nilgiris,  at  an 
elevation  of  7000  feet,  "  a  good  many 
castings,"  which  are  interesting  for  their 
great  size.  The  worms  which  eject  them  are 
seen  only  during  the  wet  season,  and  are 
reported  to  be  from  12  to  15  inches  in  length, 
and  as  thick  as  a  man's  little  finger.  These 
castings  were  collected  by  Dr.  King  after 
a  period  of  110  days  without  any  rain;  and 
they  must  have  been  ejected  either  during 
the  north-east  or  more  probably  during 
the  previous  south-west  monsoon  ;  for  their 
surfaces  had  suffered  some  disintegration  and 
they  were  penetrated  by  many  fine  roots.  A 
drawing  is  here  given  (Fig.  4)  of  one  which 


Chap.  IL  THEIR   WIDE   DISTRIBUTION.  127 

seems  to  have  best  retained  its  original  size 
and  appearance.  Notwithstanding  some  loss 
from  disintegration,  five  of  the  largest  of  these 
castings  (after  having  been  well  sun-dried) 
weighed  each  on  an  average  89'5  grammes, 


Fig.  4. 

A  casting  from  the  Nilgiii  Mountains  in  South  India ;  of 
natural  size,  engraved  from  a  photograph. 

or  above  3  oz. ;  and  the  largest  weighed 
]  23*14  grammes,  or  4^  oz., — that  is  above  a 
quarter  of  a  pound  !  The  largest  convolutions 
were  rather  more  than  one  inch  in  di  imeter ; 
but  it  is  probable  that  they  had  subsided  a  little 


128  HABITS   OF   WORMS.  Chap.  II. 

whilst  soft,  and  that  their  diameters  had  thus 
been  increased.  Some  had  flowed  so  much 
that  they  now  consisted  of  a  pile  of  almost  flat 
confluent  cakes.  All  were  formed  of  fine, 
rather  light-coloured  earth,  and  were  surpris- 
ingly hard  and  compact,  owing  no  doubt  tc 
the  animal  matter  by  which  the  particles  of 
earth  had  been  cemented  together.  They 
did  not  disintegrate,  even  when  left  for  some 
hours  in  water.  Although  they  had  been 
cast  up  on  the  surface  of  gravelly  soil,  they 
contained  extremely  few  bits  of  rock,  the 
largest  of  which  w^as  only  '15  inch  in 
diameter. 

Dr.  King  saw  in  Ceylon  a  worm  about  2 
feet  in  length  and  ^  inch  in  diameter ;  and 
he  was  told  that  it  was  a  very  common  species 
during  the  wet  season.  These  worms  must 
throw  up  castings  at  least  as  large  as  those  on 
the  Nilgiri  Mountains ;  but  Dr.  King  saw 
none  during  his  short  visit  to  Ceylon.  Suffi- 
cient facts  have  now  been  given,  showing 
that  worms  do  much  work  in  bringing  up 
fine  earth  to  the  surface  in  most  or  all  parts 
of  the  world,  and  under  the  most  diffeient 
climates. 


CHAPTEE  III. 

TOE  AMOUXT  OF  FINE  EARTH  BROUGHT  UP  llf 
WORMS  TO  THE  SURFACE. 

Rate  at  which  various  ohjects  strewed  on  tlie  surface  of  srass- 
fields  are  covered  uj)  by  the  castings  of  wdrms — The  burial  oi 
a  paved  path — The  slow  subsicience  of  great  stones  left  on  the 
surface — The  number  of  worms  which  live  within  a  given 
space — The  w.ight  of  earth  ejected  from  a  burrow,  and  from 
all  the  burrows  within  a  given  space — The  thickness  of  the 
layer  of  mould  which  the  castings  on  a  given  space  would 
form  within  a  given  time  if  uniformly  spread  out — The  slow 
rate  at  which  mould  can  increase  to  a  great  thickness — 
Conclusion. 

We  now  come  to  the  more  immediate  subject 
of  this  volume,  namely  the  amount  of  earth 
which  is  brought  up  by  worms  from  beneatli 
the  surface,  and  is  afterwards  spread  out  more 
or  less  completely  by  the  rain  and  wind.  The 
amount  can  be  judged  of  by  two  methods, — 
by  the  rate  at  which  objects  left  on  the 
surface  are  buried,  and  more  accurately  by 
weighing  the  quantity  brought  up  within  a 


[30  AMOUNT   OF   EARTH  Chap.  III. 

given   time.     We  will    begin  with    the    first 
method,  as  it  was  first  followed. 

Near  Maer  Hall  in  Staffordshire,  quick-lime 
had  been  spread  about  the  year  1827  thickly 
over  a  field  of  good  pasture-land,  which  had 
not  since  been  ploughed.  Some  square  holes 
were  dug  in  this  field  in  the  beginning  of 
October  1837 ;  and  the  sections  showed  a 
layer  of  turf,  formed  by  the  matted  roots  of 
tlie  grasses,  ^  inch  in  thickness,  beneath 
which,  at  a  depth  of  2^  inches  (or  3  inches 
from  the  surface),  a  layer  of  the  lime  in 
powder  or  in  small  lumps  could  be  distinctly 
seen  running  all  round  the  vertical  sides  of 
the  holes.  The  soil  beneath  the  layer  ot 
lime  was  either  gravelly  or  of  a  coarse  sandy 
nature,  and  differed  considerably  in  appear 
ance  from  the  overlying  dark-coloured  fine 
mould.  Coal-cinders  had  been  spread  over 
a  part  of  this  same  field  either  in  the  year 
1833  or  1834;  and  when  the  above  holes 
A^ere  dug,  that  is  after  an  interval  of  3  or  4 
years,  the  cinders  formed  a  line  of  black  spots 
round  the  holes,  at  a  deptli  of  1  inch  beneath 
the  surface,  parallel  to  and  above  the  white 
layer  of  lime-     Over  another  part  of  this  field 


Chap.  III.         BROUGHT   UP  BY   WORMS.  131 

cinders  bad  been  strewed,  only  about  balf-a- 
year  before,  and  tbese  either  still  lay  on  the 
surface  or  were  entangled  among  the  roots  of 
the  grasses ;  and  I  here  saw  the  commence- 
ment of  the  burying  process,  for  worm-cast- 
ings had  been  heaped  on  several  of  the 
smaller  fragments.  After  an  interval  of 
4|  years  this  field  was  re-examined,  and  now 
the  two  layers  of  lime  and  cinders  were  found 
almost  everywhere  at  a  greater  depth  than 
before  by  nearly  1  inch,  we  will  say  by  |  of 
an  inch.  Therefore  mould  to  an  averao:e 
thickness  of  '22  of  an  inch  had  been  annually 
brought  up  by  the  worms,  and  had  been 
spread  over  the  surface  of  this  field. 

Coal-cinders  had  been  strewed  over  another 
field,  at  a  date  which  could  not  be  positively 
ascertained,  so  thickly  that  they  formed 
(October,  1837)  a  layer,  1  inch  in  thickness 
at  a  depth  of  about  3  inches  from  the  surface. 
The  layer  was  so  continuous  that  the  over- 
lying dark  vegetable  mould  was  connected 
with  the  sub-soil  of  red  clay  only  by  the  roots 
of  the  grasses ;  and  when  these  were  broken, 
the  mould  and  the  red  clay  fell  apart.  In  a 
third  field,  on  which  coal-cinders  and  burnt 


132  AMOUNT   OF   EARTH  Cuap.  II  [ 

marl  had  been  strewed  several  times  at  un- 
known dates,  holes  were  dug  in  1842  ;  and  a 
layer  of  cinders  could  be  traced  at  a  depth 
of  3^  inches,  beneath  which  at  a  depth  of 
9^  inches  from  the  surface  there  was  a  line 
of  cinders  together  with  burnt  marl.  On  the 
sides  of  one  hole  there  were  two  layers  of 
cinders,  at  2  and  3  J  inches  beneath  the  sur- 
face ;  and  below  them  at  a  depth  in  parts 
of  9  J,  and  in  other  parts  of  10^  inches  there 
were  fragments  of  burnt  marl.  In  a  fourth 
field  two  layers  of  lime,  one  al)ove  the  other, 
could  be  distinctly  traced,  and  beneath  them 
a  layer  of  cinders  and  burnt  marl  at  a  depth 
of  from  10  to  12  inches  below  the  surface. 

A  piece  of  waste,  swampy  land  was 
enclosed,  drained,  ploughed,  harrowed  and 
thickly  covered  in  the  year  1822  with  burnt 
marl  and  cinders.  It  was  sowed  with  grass 
seeds,  and  now  supports  a  tolerably  good  but 
coarse  pasture.  Holes  were  dug  in  this  field 
in  1837,  or  15  years  after  its  reclamation, 
and  we  see  in  the  accompanying  diagram 
(Fig.  5),  reduced  to  half  of  the  natural  scale, 
that  the  turf  was  ^  inch  thick,  beneath  which 
there  was  a  layer  of  vegetable  mould  2|  inches 


Chap.  III.         BROUGHT   UP   BY   WOEMS. 


133 


thick.  This  layer  did  not  contain  fragments 
of  any  kind  ;  but  beneath  it  there  was  a  layer 
of  mould,  1^  inch  in  thickness,  full  of  fragments 


hiihl 


\i\tl\\\ 


Section,  reduced  to  half  the  natural  scale,  of  the  vegetable  mould 
in  a  field,  drained  and  reclaimed  fifteen  years  previously ;  A, 
turf;  B,  vegetable  mould  without  any  stones;  C,  mould  with 
fragments  of  burnt  marl,  coal-cinders  and  quartz  pebbles; 
D,  sub-soil  of  black,  peaty  sand  with  quartz  pebbles. 

of  burnt    marl,   conspicuous  from  their  red 
colour,  one  of  which  near  the  bottom  was  an 


134  AMOUNT   OF   EARTH  Chap.  IIL 

inch  in  length ;  and  other  fragments  of  coal- 
cinders  together  with  a  few  white  quartz 
pebhles.  Beneath  this  layer  and  at  a  depth  of 
4|  inches  from  the  surface,  the  original  black, 
peaty,  sandy  soil  with  a  few  quartz  pebbles 
was  encountered.  Here  therefore  the  frag- 
ments of  burnt  marl  and  cinders  had  been 
covered  in  the  course  of  15  years  by  a  layer 
of  fine  vegetable  mould,  only  2^  inches  in 
thickness,  excluding  the  turf.  Six  and  a  half 
years  subsequently  this  field  was  re-examined, 
and  the  iragments  were  now  found  at  from 
4  to  5  inches  beneath  the  surface.  So  that 
in  this  interval  of  6^-  years,  about  1^  inch  of 
mould  had  been  added  to  the  superficial  layer. 
I  am  surprised  that  a  greater  quantity  had 
not  been  brought  up  during  the  whole  21^ 
years,  for  in  the  closely  underlying  black, 
peaty  soil  there  were  many  worms.  It  is, 
however,  probable  that  formerly,  whilst  the 
land  remained  poor,  worms  were  scanty  ;  and 
the  mould  would  then  have  accumulated 
slowly.  The  average  annual  increase  of  thick- 
ness for  the  whole  period  is  '19  of  an  inch. 

Two  other  cases  are  worth  recording.     In 
the    spring    of    1835,    a    field,    which    had 


Ceap.  III.        BROUGHT  UP  BY  WOEMS.  135 

long  existed  as  poor  pasture  and  was  so 
swampy  that  it  trembled  slightly  when 
stamped  on,  was  thickly  covered  with  red 
sand  so  that  the  whole  surface  appeared  at 
first  bright  red.  When  holes  were  dug  in 
this  field  after  an  interval  of  about  2  J-  years, 
the  sand  formed  a  layer  at  a  depth  of  |  in. 
beneath  the  surface.  In  1842  (i.e.,  7  years 
after  the  sand  had  been  laid  on)  fresh  holes 
were  dug,  and  now  the  red  sand  formed  a 
distinct  layer,  2  inches  beneath  the  surface^ 
or  1^  inch  beneath  the  turf;  so  that  on  an 
average,  '21  inches  of  mould  had  been  annu- 
ally brought  to  the  surface.  Immediately 
beneath  the  layer  of  red  sand,  the  original 
substratum  of  black  sandy  peat  extended. 

A  grass  field,  likewise  not  far  from  Maer 
Hall,  had  formerly  been  thickly  covered  with 
marl,  and  was  then  left  for  several  years  as 
pasture ;  it  was  afterwards  ploughed.  A 
friend  had  three  trenches  dug  in  this  field 
28  years  after  the  application  of  the  marl,* 

*  This  case  is  given  in  a  postscript  to  my  paper  in  the 
'Transact.  Geolog.  Soc'  (Vol.  v.  p.  505),  and  contains  a  serious 
error,  as  in  the  account  received  I  mistook  the  figure  30  for  80, 
The  tenant,  moreover,  formerly  said  that  he  had  marled  the  field 
thirty  years  before,  hut  was  now  positive  that  thib  was  done  in 
10 


136  AMOUNT   OF   EARTH  Chap   1[I. 

and  a  layer  of  the  marl  fragments  could  be 
traced  at  a  depth,  carefully  measured,  of  12 
inches  in  some  parts,  and  of  14  inches  in 
otlisr  parts.  This  difference  in  depth  de- 
pended on  the  layer  being  horizontal,  whilst 
the  surface  consisted  of  ridges  and  furrows 
from  the  field  having  been  ploughed.  The 
tenant  assured  me  that  it  had  never  been 
turned  up  to  a  greater  depth  than  from  6  to  8 
inches ;  and  as  the  fragments  formed  an  un- 
broken horizontal  layer  from  12  to  14  inches 
beneath  the  surface,  these  must  have  been 
buried  by  the  worms  whilst  the  land  was 
in  pasture  before  it  was  ploughed,  for  other- 
wise they  would  have  been  indiscriminately 
scattered  by  the  plough  throughout  the 
whole  thickness  of  the  soil.  Four-and-a-half 
years  afterwards  I  had  three  holes  dug  in 
this  field,  in  which  potatoes  had  been  lately 
planted,  and  the  layer  of  marl-fragments  was 
now  found  13  inches  beneath  the  bottoms  of 
the  furrows,  and  therefore  probably  15  inches 


1800,  that  is  twenty-eight  years  before  the  first  examination  of 
the  field  by  my  friend.  The  error,  as  far  as  the  figure  80  is 
concerned,  was  corrected  in  an  article  by  me,  in  the  'Gardeners 
Chronicle,'  1844,  p.  218. 


Jeap.  hi.      beought  up  by  worms.  ■  137 

beneath  the  general  level  of  the  field.  It 
should,  however,  be  observed  that  the  thick- 
ness of  the  blackish  sandy  soil,  which  had 
been  thrown  up  by  the  worms  above  the  marl- 
fragments  in  the  course  of  32i  years,  would 
have  measured  less  than  15  inches,  if  the  field 
had  always  remained  ns  pasture,  for  the  soil 
would  in  this  case  have  been  much  more 
compact.  The  fragments  of  marl  almost  rested 
on  an  undisturbed  sub-stratum  of  wliite  sand 
with  quartz  pebbles  ;  and  as  this  w^ould  be 
little  attractive  to  worms,  the  mould  would 
hereafter  be  very  slowly  increased  by  their 
action. 

We  w^ili  now  give  some  cases  of  the  action 
of  worms,  on  land  differing  widely  from 
the  dry  sandy  or  the  swampy  pastures  just 
described.  The  chalk  formation  extends  all 
round  my  house  in  Kent ;  and  its  surface, 
from  having  been  exposed  during  an  immense 
period  to  the  dissolving  action  of  rain-water, 
is  extremely  irregular,  being  abruptly  fes- 
tooned and  penetrated  by  many  deep  well- 
like cavities.*     During  the  dissolution  of  tiie 

•  These  pits  or  pipes  are  still  in  process  of  formation.    During 
the  last  forty  years  I  have  seen  or  heard  of  five  cases,  in  which  a 


138  AMOUNT   OF   EABTH  Cuap.  HI. 

clialk,  the  insoluble  matter,  including  a  vast 
number    of  unrolled    flints  of  all   sizes,  lias 


circular  space,  several  feet  in  diameter,  sndt^enly  fell  in,  leaving 
on  the  field  an  open  hole  with  perpendicular  sides,  some  feet  in 
depth.  This  occurred  in  one  of  my  own  fields,  whilst  it  was 
being  rolled,  and  the  hinder  quarters  of  the  shaft  horse  fell  in ;  two 
or  three  cart-loads  of  rubbish  were  required  to  fill  up  the  hole. 
The  subsidence  occurred  where  there  was  a  broad  depression,  as 
if  the  surface  had  fallen  in  at  several  former  periods.  I  heard 
of  a  hole  which  must  have  been  suddenly  formed  at  the  bottom 
of  a  small  shallow  pool,  where  sheep  had  been  washed  during 
many  years,  and  into  which  a  man  thus  occupied  fell  to  his  great 
terror.  The  rain-water  over  this  whole  district  sinks  perpen- 
dicularly into  the  ground,  but  the  chalk  is  more  porous  in  certain 
places  than  in  others.  Thus  the  drainage  from  the  overlying 
clay  is  directed  to  certain  points,  where  a  greater  amount  of  cal- 
careous matter  is  dissolved  than  elsewheie.  Even  narrow  open 
channels  are  sometimes  formed  in  the  solid  chalk.  As  the  chalk 
is  slowly  dissolved  over  the  whole  country,  but  more  in  some 
parts  than  in  others,  the  undissolved  residue — that  is  the  over- 
lying mass  of  red  clay  with  flints, — likewise  sinks  slowly  down, 
and  tends  to  fill  up  the  pipes  or  cavities.  But  the  upper  part 
of  the  red  clay  holds  together,  aided  probably  by  the  roots  of 
plants,  for  a  longer  time  than  the  lower  parts,  and  thus  forms 
a  roof,  which  sooner  or  later  falls  in,  as  in  the  above  mentioned 
five  cases.  The  downward  movement  of  the  clay  may  be  com- 
pared with  that  of  a  glacier,  but  is  incomparably  slower ;  and  this 
movement  accounts  for  a  singular  fact,  namely  that  the  much 
elongated  flints  which  are  embedded  in  the  clialk  in  a  nearly 
horizontal  position,  are  commonly  found  standing  nearly  or  quite 
upright  in  the  red  clay.  This  fact  is  so  common  that  the  work- 
men assured  me  that  this  was  their  natural  position.  1  roughly 
measured  one  which  stood  vertically,  and  it  was  of  the  same 
length  and  of  the  same  relative  thickness  as  one  of  my  arms. 
These  elongated  flints  must  get  placed  in  their  upiight  position, 


Chap.  III.        BROUGHT   UP  BY  WOEMS.  139 

been  left  on  the  surface  and  forms  a  Led  oi 
stiff  red  clay,  full  of  flints,  and  generally 
from  6  to  14  feet  in  thickness.  Over  the  red 
clay,  wherever  the  land  has  long  remained  as 
pasture,  there  is  a  layer  a  few  inches  in 
thickness,  of  dark -coloured  vegetable  mould. 

A  quantity  of  broken  chalk  was  spread, 
on  December  20,  1842,  over  a  part  of  a  field 
near  my  house,  which  had  existed  as  pasture 
certainly  for  30,  probably  for  twice  or  thrice 
as  many  years.  The  chalk  was  laid  on  the 
land  for  the  sake  of  observing  at  some  future 
period  to  what  depth  it  would  become  buried. 
At  the  end  of  November,  1871,  that  is  after  an 
interval  of  29  years,  a  trench  was  dug  across 
this  part  of  the  field;  and  a  line  of  white  nodules 
could  be  traced  on  both  sides  of  the  trench,  at 
a  depth  of  7  inches  from  the  surface.  The 
mould,    therefore,    (excluding    the  turf)  had 


on  the  same  principle  that  a  trunk  of  a  tree  left  on  a  glacier 
assumes  a  position  parallel  to  the  line  of  motion.  The  flints 
in  the  clay  which  form  almost  half  its  bulk,  are  very  often 
broken,  though  not  rolled  or  abraded ;  and  this  may  be  ac- 
aounted  for  by  their  mutual  pressure,  whilst  the  whole  mass  is 
subsiding.  1  may  add  that  the  chalk  here  appears  to  have  been 
originally  covered  in  parts  by  a  thin  bed  of  fine  sand  with  some 
perfectly  rounded  flint  pebbles,  probably  of  Tertiary  age ;  for  such 
sand  often  partly  fills  up  the  deeper  pits  or  cavities  in  the  chalk. 


1 40  AMOUNT    OF   EARTH  Chap.  III. 

here  been  thrown  np  at  an  average  rate  of 
•22  inches  per  year.  Beneath  the  line  of 
chalk  nodules  there  was  in  parts  hardly  any 
fine  earth  free  of  flints,  while  in  other  parts 
there  was  a  layer,  2|  inches  in  thickness.  In 
this  latter  case  the  mould  was  altogether  9-i 
inches  thick  ;  and  in  one  such  spot  a  nodule 
of  chalk  and  a  smooth  flint  pebble,  both  of 
which  must  have  been  left  at  some  former 
time  on  the  surface,  were  found  at  this 
depth.  At  from  11  to  12  inches  beneath 
the  surface,  the  undisturbed  reddish  clay,  full 
of  flints,  extended.  The  appearance  of  the 
above  nodules  of  chalk  surprised  me  much 
at  first,  as  they  closely  resembled  water- 
worn  pebbles,  whereas  the  freshly-broken 
fragments  had  been  angular.  But  on  ex- 
amining the  nodules  w^ith  a  lens,  they  no 
longer  appeared  water-worn,  for  their  surfaces 
were  pitted  through  unequal  corrosion,  and 
minute,  sharp  points,  formed  of  broken  fossil 
shells,  projected  from  them.  It  was  evident 
that  the  corners  of  the  original  fragments  of 
chalk  had  been  wholly  dissolved,  from  pre- 
senting a  large  surface  to  the  carbonic  acid 
dissolved  in  the  rain-water  and  to  that  gener- 


Chap.  III.        BROUGHT   UP  BY   WORMS.  141 

ated  in  soil  containing  vegetable  matter,  as 
well  as  to  the  hiimns-acids.*  The  projecting 
corners  would  also,  relatively  to  the  other 
parts,  have  been  embraced  by  a  larger  num- 
ber of  living  rootlets  ;  and  these  have  the 
power  of  even  attacking  marble,  as  Sachs  has 
shown.  Thus,  in  the  course  of  29  years, 
buried  angular  fragments  of  chalk  had  been 
converted  into  well-rounded  nodules. 

Another  part  of  this  same  field  was  mossy, 
and  as  it  was  thought  that  sifted  coal-cinders 
would  improve  the  pasture,  a  thick  layer  was 
spread  over  this  part  either  in  1842  or  1843 
and  another  layer  some  years  afterwards. 
In  1871  a  trench  was  here  dug,  and  many 
cinders  lay  in  a  line  at  a  depth  of  7 
inches  beneath  the  surface,  with  another  line 
at  a  depth  of  5  J  inches  parallel  to  the  one 
beneath.  In  another  part  of  this  field, 
wdiich  had  formerly  existed  as  a  separate 
one,  and  which  it  was  believed  had  been 
pasture-land  for  more  than  a  century,  trenches 
were  dug  to  see  how  thick  the  vegetable 
mould  was.  By  chance  the  first  trench  was 
made  at  a  spot  where  at  some  former  period, 

*  S.  W.  Johnson,  '  IIow  Crops  Foed,'  1870,  p.  139 


112  AMOUNT   OF   EARTH  Chap.  TIL 

certainly  more  than  forty  years  before,  a 
large  hole  had  been  filled  up  with  coarse  red 
clay,  flints,  fragments  of  chalk,  and  gravel ; 
«ind  here  the  fine  vegetable  mould  was  only 
from  4^  to  4f  inches  in  thickness.  In 
another  and  undisturbed  place,  the  mould 
varied  much  in  thickness,  namely  from  6^ 
to  8 1  inches ;  beneath  which  a  few  small 
fragments  of  brick  were  found  in  one 
place.  From  these  several  cases,  it  would 
appear  that  during  the  last  29  years  mould 
has  been  heaped  on  the  surface  at  an 
average  annual  rate  of  from  '2  to  '22  of  an 
inch.  But  in  this  district  when  a  ploughed 
field  is  first  laid  down  in  grass,  the  mould 
accumulates  at  a  much  slower  rate.  The 
rate,  also,  must  become  very  much  slower 
after  a  bed  of  mould,  several  inches  in  thick- 
ness, has  been  formed  ;  for  the  worms  then 
live  chiefly  near  the  surface,  and  burrow 
down  to  a  greater  depth  so  as  to  bring  up 
fresh  earth  from  below,  only  during  the 
winter  when  the  weather  is  very  cold  (at 
which  time  worms  were  found  in  this  field  at 
a  depth  of  26  inches)  and  during  summer 
when  the  weather  is  very  dry. 


Chap.  III.        BROUGHT   UP  BY   WORMS.  143 

A  field,  wliicti  adjoins  the  one  just  de- 
scribed, slopes  in  one  part  rather  steeply 
(viz.,  at  from  10°  to  15°);  this  part  was  last 
ploughed  in  1841,  was  then  harrowed  and 
left  to  become  pasture-land.  For  several 
years  it  was  clothed  with  an  extremely  scant 
vegetation,  and  was  so  thickly  covered  with 
small  and  large  flints  (some  of  them  half  as 
large  as  a  child's  head)  that  the  field  was 
always  called  by  my  sons  "  the  stony  field." 
When  they  ran  down  the  slope  the  stones 
clattered  together.  I  remember  doubting 
whether  I  should  live  to  see  these  larger  flints 
covered  with  vegetable  mould  and  turf.  But 
the  smaller  stones  disappeared  before  many 
years  had  elapsed,  as  did  every  one  of  tlie 
larger  ones  after  a  time ;  so  that  after  thirty 
years  (1871)  a  horse  could  gallop  over  the 
compact  turf  from  one  end  of  the  field  to  the 
other,  and  not  strike  a  single  stone  with  his 
shoes.  To  anyone  who  remembered  the 
aj>pearance  of  the  field  in  1842,  the  transfor- 
mation was  wonderful.  This  was  certainly 
the  work  of  the  worms,  for  though  castings 
were  not  frequent  for  several  years,  yet  some 
were    thrown    up   month   after   month,    and 


114  AMOUNT   OF   EARTH  Chap.  Ill 

tljese  gradually  increased  in  numbers  as  tlio 
pasture  improved.  In  the  year  1871  a 
trench  was  dug  on  the  above  slope,  and  tlie 
blades  of  grass  were  cut  off  close  to  the  roots, 
so  that  the  thickness  of  the  turf  and  of  the 
vegetable  mould  could  be  measured  accur- 
ately. The  turf  was  rather  less  than  half  an 
inch,  and  the  mould,  which  did  not  contain 
any  stones,  2^  inches  in  thickness.  Beneath 
this  lay  coarse  clayey  earth  full  of  flints,  like 
that  in  any  of  the  neighbouring  ploughed 
fields.  This  coarse  earth  easily  fell  apart 
from  the  overlying  mould  when  a  spit  was 
lifted  up.  The  average  rate  of  accumulation 
of  the  mould  during  the  whole  thirty  years 
was  only  '083  inch  per  year  (i.e.,  nearly  one 
inch  in  twelve  years) ;  but  the  rate  must 
have  been  m.uch  slower  at  first,  and  after- 
wards considerably  quicker. 

The  transformation  in  the  appearance  of 
this  field,  which  had  been  effected  beneath 
my  eyes,  was  afterwards  rendered  the  more 
Bt]  iking,  when  I  examined  in  Knole  Park 
a  dense  forest  of  lofty  beech-trees,  beneath 
which  nothing  grew.  Here  the  ground  was 
thickly  strewed  with  large  naked  stones,  and 


CuAP.  IIL        BEOUGHT   UP   BY   WOHMS.  145 

worm-castings  were  almost  wholly  absent. 
Obscure  lines  and  irregularities  on  the  sur- 
face indicated  that  the  land  had  been  cul- 
tivated some  centuries  ago.  It  is  probable 
that  a  thick  wood  of  young  beech-trees 
sprung  up  so  quickly,  that  time  enough  was 
not  allowed  for  worms  to  cover  up  the  stones 
with  their  castings,  before  the  site  became 
unfitted  for  their  existence.  Anyhow  the 
contrast  between  the  state  of  the  now 
miscalled  "  stony  field,"  well  stocked  with 
worms,  and  the  present  state  of  the  ground 
beneath  the  old  beech-trees  in  Knole  Park, 
where  worms  appeared  to  be  absent,  was 
striking. 

A  narrow  path  running  across  part  of  my 
lawn  was  paved  in  1843  with  small  flag- 
stones, set  edgeways ;  but  worms  threw  up 
many  castings  and  weeds  grew  thickly  be- 
tween them.  During  several  years  the  path 
was  weeded  and  swept ;  but  ultimately  the 
weeds  and  worms  prevailed,  and  the 
gardener  ceased  to  sweep,  merely  mowing  off 
the  weeds,  as  often  as  the  lawn  was  mowed. 
The  path  soon  became  almost  covered  u]), 
and    after   several   years  no  trace   of   it  wais 


14G  AMOUNT   OF   EAKTH  Chap,  llh 

lef^.  On  removing,  in  1877,  the  thin  over* 
lying  layer  of  turf,  the  small  flag-stones,  all 
in  their  proper  places,  were  found  covered 
by  an  inch  of  fine  mould. 

Two  recently  published  accounts  of  sub- 
stances strewed  on  the  surface  of  pasture-land, 
having  become  buried  through  the  action  of 
worms,  may  be  here  noticed.  The  Rev. 
H.  C.  Key  had  a  ditch  cut  in  a  field,  over 
which  coal-ashes  had  been  spread,  as  it  was 
believed,  eighteen  years  before ;  and  on  the 
clean-cut  perpendicular  sides  of  the  ditch,  at  a 
depth  of  at  least  seven  inches,  there  could  be 
seen,  for  a  length  of  60  yards,  "  a  distinct,  very 
''even,  narrow  line  of  coal-ashes,  mixed  with 
"  small  coal,  perfectly  parallel  with  the  top- 
sward."*  This  parallelism  and  the  length  of  the 
section  gives  interest  to  the  case.  Secondly, 
Mr.  Dancer  statesy  that  crushed  bones  had  been 
thickly  strewed  over  a  field  ;  and  "  some  years 
"  afterwards  "  these  were  found  "  several  inches 
''below  the  surface,  at  a  uniform  depth." 
Worms  appear  to  act  in  the  same  manner  in 
New  Zealand  as  in  Europe  ;  for  Professor  J. 

*  '  Nature,'  November  1877,  p.  28. 

♦  *  Proc.  Phil.  Soc'  of  Manchester,  1877,  p.  247, 


Chap   III.        BROUGHT   UP   BY  WORMS.  147 

von  Haast  has  described  *  a  section  near  the 
coast,  consisting  of  mica-schist,  "  covered  by 
"5  or  6  feet  of  loess,  above  which  about  ]  2 
"  inches  of  vegetable  soil  had  accumulated.'* 
Between  the  loess  and  the  mould  there  was 
a  layer  from  3  to  6  inches  in  thickness, 
consisting  of  "cores,  implements,  flakes,  and 
*'  chips,  all  manufactured  from  hard  basaltic 
"rock."  It  is  therefore  probable  that  the 
aborigines,  at  some  former  period,  had  left 
these  objects  on  the  surface,  and  that  they 
had  afterwards  been  slowly  covered  up  by 
the  castings  of  worms. 

Farmers  in  England  are  well  aware  that 
objects  of  all  kinds,  left  on  the  surface  of 
pasture-land,  after  a  time  disappear,  or,  as 
they  say,  work  themselves  downwards.  How 
powdered  lime,  cinders,  and  heavy  stones, 
can  work  down,  and  at  the  same  rate, 
through  the  matted  roots  of  a  grass-covered 
surface,  is  a  question  which  has  probably 
never  occurred  to  them.f 

•  *  Trans,  of  the  New  Zealand  Institute,'  vol.  xii.,  1880,  p.  152. 

t  Mr.  Lindsay  Carnagie,  in  a  letter  (June  1838)  to  Sir  C  Lyell, 
remarks  that  Scotch  farmers  are  afraid  of  putting  lime  on 
ploughed  land  until  just  before  it  is  laid  down  for  pasture,  from 
a  beUef  that  it  has  some  tendency  to  sink.     He  adds  :  "  Some 


118  GREAT   STONES  Cn^r.  Ill, 

The  Sinking  of  great  Stones  through  the 
Action  of  Worms. — When  a  stone  of  large 
size  and  of  irregular  shape  is  left  on  the 
surface  of  the  ground,  it  rests,  of  conrso, 
on  the  more  protuberant  parts  ;  but  worms 
soon  fill  up  with  their  castings  all  the  hollow 
spaces  on  the  lower  side ;  for,  as  Hensen  re- 
marks, they  like  the  shelter  of  stones.  As 
soon  as  the  hollows  are  filled  up,  the  worms 
eject  the  earth  which  they  have  swallowed 
beyond  the  circumference  of  the  stones ; 
and  thus  the  surface  of  the  ground  is  raised 
all  round  the  stone.  As  the  burrows  ex- 
cavated directly  beneath  the  stone  after  a 
time  collapse,  the  stone  sinks  a  little.*  Hence 
it    is,  that  boulders  which    at   some   ancient 


years  since,  in  autumn,  I  laid  lime  on  an  oat-stubble  and  ploughed 
it  down  ;  thus  bringing  it  into  immediate  contact  with  the  dead 
vegetable  matter,  and  securing  its  thorough  mixture  through  the 
means  of  all  the  subsequent  operations  of  fallow.  In  consequence 
of  the  above  prejudice,  I  was  considered  to  have  committed  a 
great  fault ;  but  the  result  was  eminently  successful,  and  the 
practice  was  jpartially  followed.  By  means  of  Mr.  Darwin's 
observations,  I  think  the  prejudice  will  be  removed." 

*  This  conclusion,  which,  as  we  shall  immediately  see.  is  fully 
justifipd,isofsome  little  importance,  as  the  so-called  bench-stones, 
which  sun-eyors  fix  in  the  ground  as  a  record  of  their  levels, 
may  in  time  become  false  standards.  My  son  Horace  intends  al 
»ome  future  period  to  ascertain  how  far  this  has  occurred. 


CiiAP.  III.        UNDERMINED   BY   WORMS.  149 

period  have  rolled  down  from  a  rocky  moun- 
tain or  cliff  on  to  a  meadow  at  its  base,  are 
always  somewliat  embedded  in  the  soil ;  and, 
when  removed,  leave  an  exact  impression  of 
their  lower  surfaces  in  the  nnder-lying  fine 
mould.  If,  however,  a  boulder  is  of  such 
huge  dimensions,  that  the  earth  beneath  is 
kept  dry,  such  earth  will  not  be  inhabited 
by  worms,  and  the  boulder  will  not  sink 
into  the  ground. 

A  lime-kiln  formerly  stood  in  a  grass-field 
near  Leith  Hill  Place  in  Surrey,  and  was 
pulled  down  35  years  before  my  visit ; 
all  the  loose  rubbish  had  been  carted  away, 
excepting  three  large  stones  of  quartzose 
sandstone,  which  it  was  thought  might  here- 
after be  of  some  use.  An  old  workman  re- 
membered that  they  had  been  left  on  a  bare 
surface  of  broken  bricks  and  mortar,  close  to 
the  foundations  of  the  kiln  ;  but  the  whole 
surrounding  surface  is  now  covered  with  turf 
and  mould.  The  two  largest  of  these  stones 
had  never  since  been  moved ;  nor  could  this 
easily  have  been  done,  as,  when  I  had  them 
removed,  it  was  the  work  of  two  men  with 
levers.     One    of  these    stones,    and    not    the 


150  GREAT   STONES  Chap.  III. 

largest,  was  64  inches  long,  17  inches  broad, 
and  from  9  to  10  inches  in  thickness.  Its 
lower  surface  was  somewhat  protuberant  in 
the  middle ;  and  this  part  still  rested  on 
broken  bricks  and  mortar,  showing  the  truth 
of  the  old  workman's  account.  Beneath  the 
brick  rubbish  the  natural  sandy  soil,  full  of 
fragments  of  sandstone  was  ibund  ;  and  this 
could  have  yielded  very  little,  if  at  all,  to 
the  \veight  of  the  stone,  as  might  have  been 
expected  if  the  sub-soil  had  been  clay.  The 
surface  of  the  field,  for  a  distance  of  about 
9  inches  round  the  stone,  gradually  sloped  up 
to  it,  and  close  to  the  stone  stood  in  most 
places  about  4  inches  above  the  surrounding 
ground.  The  base  of  the  stone  was  buried 
from  1  to  2  inches  beneath  the  gen(?ral  level, 
and  the  upper  surface  projected  about  8 
inches  above  this  level,  or  about  4  inches 
above  the  sloping  border  of  turf.  After  tl.e 
removal  of  the  stone  it  became  evident  that 
one  of  its  pointed  ends  must  at  first  have 
stood  clear  above  the  ground  by  some  inches, 
but  its  upper  surface  was  now  on  a  level 
v^ith  the  surrounding  turf.  When  the  stone 
v/as   removed,   an    exact    cast    of    its   lowei 


Chap.  III.        UNDERMINED   BY   WORMS.  151 

side,  forming  a  shallow  crateriform  hollow, 
was  left^  the  inner  surface  of  which  consisted 
of  fine  black  mould,  excepting  where  the 
more  protuberant  parts  rested  on  the  brick- 
tubbish.  A  transverse  section  of  this  stone, 
together  with  its  bed,  drawn  from  measure- 
ments made  after  it  had  been  displaced,  is 
here  given  on  a  scale  of  ^  inch  to  a  foot 
(Fig.    6).      The   turf-covered    border   which 


irmtP^^       .  ^J:!ii^l  ^  ^-v 


Fig.  6. 

Transverse  section  across  a  large  stone,  which  had  lain  on  a 

grass-field  for  35  years.     A  A,  general  level  of  the  field.  The 

underlying  brick  rubbish  has  not  been  represented.  Scale 
i  inch  to  one  foot. 

sloped  up  to  the  stone,  consisted  of  fine 
vegetable  mould,  in  one  part  7  inches  in 
thickness.  This  evidently  consisted  of  worm- 
castings,  several  of  which  had  been  recently 
ejected.  The  whole  stone  had  sunk  in  the 
thirty-fi.ve  years,   as    far   as    I   could  judge, 

about  1^-  inch  ;  and  this  must  have  been  due 
11 


152  GREAT   STONES  Chap.  Ill 

to  the  brick-rubbish  beneath  the  more  pro- 
tuberant parts  having  been  undermined  by 
worms.  At  this  rate  the  upper  surface  of  the 
stone,  if  it  had  been  left  undisturbed,  would 
have  sunk  to  the  general  level  of  the  field 
in  247  years ;  but  before  this  could  have 
occurred,  some  earth  would  have  been  washed 
down  by  heavy  rain  from  the  castings  on  the 
raised  border  of  turf  over  the  upper  surface 
of  the  stone. 

The  second  stone  was  larger  than  the  one 
just  described,  viz.,  67  inches  in  length,  39  in 
breadth,  and  15  in  thickness.  The  lower 
surface  was  nearly  flat,  so  that  the  worms 
must  soon  have  been  compelled  to  eject  their 
castings  beyond  its  circumference.  The  stone 
as  a  whole  had  sunk  about  2  inches  into  the 
ground.  At  this  rate  it  would  have  required 
262  years  for  its  upper  surface  to  have  sunk 
to  the  general  level  of  the  field.  The  up- 
wardly sloping,  turf-covered  border  round 
the  stone  was  broader  than  in  the  last  case, 
viz.,  from  14  to  16  inches;  and  why  this 
should  be  so,  I  could  see  no  reason.  In  most 
parts  this  border  was  not  so  high  as  in  the 
last  case,  viz.,  from  2  to  2|  inches,  but  in  one 


Chap.  III.        UNDERMINED   BY   WOEMS.  153 

place  it  was  as  much  as  5^.  Its  average 
height  close  to  the  stone  was  prohably  about 
3  inches,  and  it  thinned  out  to  nothing.  If 
so,  a  layer  of  fine  earth,  15  inches  in  breadth 
and  1^  inch  in  average  thickness,  of  sufficient 
length  to  surround  the  whole  of  the  much 
elongated  slab,  must  have  been  brought  up 
by  the  worms  in  chief  part  from  beneath  the 
stone  in  the  course  of  35  years.  This 
amount  would  be  amply  sufficient  to  account 
for  its  having  sunk  about  2  inches  into  the 
ground ;  more  especially  if  we  bear  in  mind 
that  a  good  deal  of  the  finest  earth  would 
have  been  washed  by  heavy  rain  from  the 
castings  ejected  on  the  sloping  border  down 
to  the  level  of  the  field.     Some  fresh  castino-s 

o 

were  seen  close  to  the  stone.  Nevertheless, 
on  digging  a  large  hole  to  a  depth  of  18 
inches  where  the  stone  had  lain,  only  two 
worms  and  a  few  burrows  were  seen,  although 
the  soil  was  damp  and  seemed  favourable  for 
worms.  There  were  some  large  colonies  of 
ants  beneath  the  stone,  and  possibly  since 
their  establishment  the  worms  had  decreased 
in  number. 

The   third   stone  was  only  about   half  as 


154  GREAT   STONES  Chap.  TIT. 

large  as  the  others ;  and  two  strong  boys 
could  together  have  rolled  it  over.  I  have 
no  doubt  that  it  had  been  rolled  over  at  a 
moderately  recent  time,  for  it  now  lay  at 
some  distance  from  the  two  other  stones  at 
the  bottom  of  a  little  adjoining  slope.  It 
rested  also  on  fine  earth,  instead  of  partly  on 
brick-rubbish.  In  agreement  with  this  con- 
clusion, the  raised  surrounding  border  of 
turf  was  only  1  inch  high  in  some  parts,  and 
2  inches  in  other  parts.  There  were  no 
colonies  of  ants  beneath  this  stone,  and  on 
digging  a  hole  w^here  it  had  lain,  several 
burrows  and  worms  were  found. 

At  Stonehenge,  some  of  the  outer  Druidical 
stones  are  now  prostrate,  having  fallen  at  a 
remote  but  unknown  period ;  and  these  have 
become  buried  to  a  moderate  depth  in  the 
ground.  They  are  surrounded  by  sloping 
borders  of  turf,  on  which  recent  castings  were 
seen.  Close  to  one  of  these  fallen  stones, 
which  was  17  ft.  long,  6  ft.  broad,  and  28. | 
inches  thick,  a  hole  was  dug  ;  and  here  the 
vegetable  mould  was  at  kast  9^  inches  in 
thickness.  At  this  depth  a  flint  was  found, 
and  a  little  higher  up  on  one  side  of  the  hole 


Chap.  III.        UNDERMINED   BY   WORMS.  155 

a  fragment  of  glass.  The  base  of  the  stone 
Jay  about  9^  incbes  beneath  the  level  of  the 
surrounding  ground,  and  its  upper  surface 
1 9  inches  above  the  ground. 

A  hole  was  also  dug  close  to  a  second  huge 
stone,  which  in  falling  had  broken  into  two 
pieces;  and  this  must  have  happened  long 
ago,  judging  from  the  weathered  aspect  of 
the  fractured  ends.  The  base  was  buried  to 
a  depth  of  10  inches,  as  was  ascertained  by 
driving  an  iron  skewer  horizontally  into  the 
ground  beneath  it.  The  vegetable  mould 
forming  the  turf-covered  sloping  border  round 
the  stone,  on  which  many  castings  had  re- 
cently been  ejected,  was  10  inches  in  thick- 
ness ;  and  most  of  this  mould  must  have  been 
brought  up  by  worms  from  beneath  its  base. 
Ai  a  distance  of  8  yards  from  the  stone,  the 
mould  was  only  5 J  inches  in  thickness  (with 
a  piece  of  tobacco  pipe  at  a  depth  of  4  inches), 
and  this  rested  on  broken  flint  and  chalk 
which  could  not  have  easily  yielded  to  the 
pressure  or  weight  of  the  stone. 

A  straight  rod  was  fixed  horizontally  (by 
the  aid  of  a  spirit-level)  across  a  third  fallen 
stone,  which  was  7  feet  9  inches  long  ;  and  the 


156  GREAT   STONES  Chap.  III. 

contour  of  the  projecting  parts  and  of  the  ad- 
joining ground,  which  was  not  quite  level, 
was  thus  ascertained,  as  shown  in  the  ac- 
companying diagram  (Fig.    7)  on  a  scale  of 


Grass 


Fig.  7. 

Section  thrmigh  one  of  the  fallen  Dmidical  stones  at  Stonehenge, 
showing  how  much  it  had  sunk  into  the  ground.  Scale  h  inch 
to  1  foot. 

^  inch  to  a  foot.  The  turf-covered  border 
sloped  up  to  the  stone  on  one  side  to  a 
height  of  4  inches,  and  on  the  opposite  side 
to  only  2i  inches  above  the  general  level. 
A  hole  was  dug  on  the  eastern  side,  and  the 
base  of  the  stone  was  here  found  to  lie  at  a 
depth  of  4  inches  beneath  the  general  level 
of  the  ground,  and  of  8  inches  beneath  the 
top  of  the  sloping  turf-covered  border. 

Sufficient   evidence   has    now   been   given 
showing  that  small  objects  left  on  the  surface 


Chap.  III.        UNDEKMINEB   BY   WOEMS.  157 

of  the  land  where  worms  abound  soon  gel 
buried,  and  that  large  stones  sink  slowly 
downwards  through  the  same  means.  Every 
step  of  the  process  could  be  followed,  from  the 
accidental  deposition  of  a  single  casting  on  a 
small  object  lying  loose  on  the  surface,  to  its 
being  entangled  amidst  the  matted  roots  of 
the  turf,  and  lastly  to  its  being  embedded  in 
the  mould  at  various  depths  beneath  the 
surface.  When  the  same  field  was  re-ex- 
amined after  the  interval  of  a  few  years,  such 
objects  were  found  at  a  greater  depth  than 
before.  The  straightness  and  regularity  of 
the  lines  formed  by  the  embedded  objects, 
and  their  parallelism  with  the  surface  of  the 
land,  are  the  most  striking  features  of  the 
case ;  for  this  parallelism  shows  how  equably 
the  worms  must  have  w^orked;  the  result 
being,  however,  partly  the  effect  of  the  wash- 
ing down  of  the  fresh  castings  by  rain.  The 
specific  gravity  of  the  objects  does  not  affect 
their  rate  of  sinking,  as  could  be  seen  by 
porous  cinders,  burnt  marl,  chalk  and  quartz 
pebbles,  having  all  sunk  to  the  same  depth 
within  the  same  time.  Considering  the 
nature  of  the  substratum,  which  at  Leith  Hill 


L58  NUMBER   OF   WORMS.  Chap.  III. 

Place  was  sandy  soil  including'  many  bits  of 
rock,  and  at  Stonehenge,  clialk-rubble  with 
broken  flints;  considering,  also,  the  presence 
of  the  turf-covered  sloping  border  of  mould 
round  the  great  fragments  of  stone  at  botb 
tliese  places,  their  sinking  does  not  appear  to 
have  been  sensibly  aided  by  their  weight, 
though  this  was  considerable.* 

Oil  the  number  of  ivorms  which  live  within 
a  given  space. — We  will  now  show,  firstly, 
what  a  vast  number  of  worms  live  unseen  by 
us  beneath  our  feet,  and,  secondly,  the  actual 
weight  of  the  earth  which  they  bring  up  to 
the  surface  within  a  given  space  and  within 
a  given  time.  Hensen,  who  has  published  so 
full  and  interesting  an  account  of  the  habits 
of  worms,!  calculates,  from  the  number  which 
he  found  in  a  measured  space,  that  there  must 
exist  133,000  living  worms   in  a  hectare  of 

»  Mr.  R.  Mallet  remarks  ('  Quarterly  Journal  of  Geolog.  Soc, 
vol.  xxxiii.,  1877,  p.  745)  that  "  the  extent  to  which  the  ground 
beneath  the  foundations  of  ponderous  architectural  structures, 
FiCli  as  cathedral  towers,  has  been  known  to  become  compressed, 
is  as  remarkable  as  it  is  instructive  and  curious.  The  amount 
of  depression  in  some  cases  may  be  measured  by  feet."  He 
i'lstances  the  Tower  of  Pisa,  but  adds  that  it  was  founded  on 
"  vlense  clay." 

t  '  Zoitschrift  fiir  wissensch.  Zoolog.'  Bd.  xxviii.,  1877,  p.  354 


Ceap   III.  KUMBER   OF   WORMS.  159 

land,  or  53,767  in  an  acre.  This  latter 
Dinnber  of  worms  would  weigh  356  pounds, 
raking  Hensen's  standard  of  the  weight  of  a 
?gingle  worm,  namely,  one  gram.  It  should, 
however,  be  noted  that  this  calculation  is 
founded  on  the  numbers  found  in  a  garden, 
and  Hensen  believes  that  worms  are  here 
twice  as  numerous  as  in  corn-fields.  The 
above  result,  astonishing  though  it  be,  seems 
to  me  credible,  judging  from  the  number  of 
worms  which  I  have  sometimes  seen,  and 
from  the  number  daily  destroyed  by  birds 
without  the  species  being  exterminated. 
Some  barrels  of  bad  ale  were  left  on  Mr. 
Miller's  land,*  in  the  hope  of  making  vinegar, 
but  the  vinegar  proved  bad,  and  the  barrels 
were  upset.  It  should  be  premised  that  acetic 
acid  is  so  deadly  a  poison  to  worms  that 
Perrier  found  that  a  glass  rod  dipped  into 
this  acid  and  then  into  a  considerable  body  of 
;vater  in  which  worms  were  immersed,  in- 
variably killed  them  quickly.  On  the  morn- 
ing after  the  barrels  had  been  upset,  "  the 
''  heaps   of  worms   which   lay    dead   on   the 

•  See  Mr.  Dancer's  paper  in  '  Proc.  Phil.  Soc.  of  Manchester, 
1877,  p.  248. 


160  WEIGHT   OF  EARTH  Chap.  IIL 

"  ground  were  so  amazing,  that  if  Mr.  Miller 
''  had  not  seen  them,  he  could  not  have 
'•thought  it  possible  for  such  numbers  to 
"  have  existed  in  the  space."  As  further  evi- 
dence of  the  large  number  of  worms  which 
live  in  the  ground,  Hensen  states  that  he 
found  in  a  garden  sixty-four  open  burrows  in 
a  space  of  14i  square  feet,  that  is,  nine  in 
2  square  feet.  Bat  the  burrows  are  some- 
times much  more  numerous,  for  when  digging 
in  ^  grass-field  near  Maer  Hall,  I  found  a 
cake  of  dry  earth,  as  large  as  my  two  open 
hands,  which  was  penetrated  by  seven  bur- 
rows, as  large  as  goose-quills. 

Weight  of  the  earth  ejected  from  a  single 
burrow^  and  from  all  the  burrows  within  a 
given  space. — With  respect  to  the  weight  of 
the  earth  daily  ejected  by  worms,  Hensen 
found  that  it  amounted,  in  the  case  of  some 
worms  which  he  kept  in  confinement,  and 
which  he  appears  to  have  fed  with  leaves,  to 
only  0*5  gram,  or  less  than  8  grains  per 
diem.  But  a  very  much  larger  amount 
must  be  ejected  by  worms  in  their  natural 
state,  at  the  periods  when  they  consume  earth 
as  food  instead  of  leaves,  and  when  they  are 


Chap.  III.        BROUGHT   UP   BY   WORMS.  161 

making  deep  burrows.  This  is  rendered 
almost  certain  by  the  following  weights  of  the 
castings  thrown  up  at  tlie  mouths  of  single 
burrows ;  the  whole  of  which  appeared  to 
have  been  ejected  within  no  long  time,  as  was 
certainly  the  case  in  several  instances.  The 
castings  were  dried  (excepting  in  one  specified 
instance)  by  exposure  during  many  days  to 
the  sun  or  before  a  hot  fire. 


Weight  of  the  Castings  accumulated  at  the  mouth 
of  a  single  buerow. 

Ounces. 

(1.)  Down,  Kent  (sub-soil  red  clay,  full  of  flints,  over-\ 
lying  the  chalk).       The   largest   casting  which  1 1 
could   find  on  the   flanks  of  a   steep  valley,  the?     3*98 
sub-soil  being  here  shallow.     In  this  one  case,  the 
casting  was  not  well  dried    ..  ..  ,.  ..^ 

(2.)  Down. — Largest  casting  which  I  could  find  (con- 
sisting chiefly  of  calcareous  matter),  on  extremely 
poor  pasture  land  at  the  bottom  of  the  valley 
mentioned  under  (1.) 

(3.)  Down. — A  large  casting,  but  not  of  unusual  size,  j 

from  a  nearly  level  field,  poor  pasture,  laid  down  in  \     1'22 
grass  about  35  years  before..  ..  ..  ..  ) 

(4.)  Down. — Average  weight  of  11  not  large  castings] 

ejected  on  a  sloping  surface  on  my  lawn,  after  they  I      ^  _ 
had  suffered  some  loss  of  weight  from  being  exposed  [ 
during  a  considerahle  length  of  time  to  rain  ..  ) 

(5.)  Near  Nice  in  France. — Average  weight  of  121 
castings  of  ordinary  dimensions,  collected  by  Dr. 
King  on  land  which  had  not  been  mown  for  a  long 
time  and  where  worms  abounded,  viz.,  a  lawn  pro- 
tected by  shrubberies,  near  the  sea  ;  soil  sandy  and 
calcareous ;  the.se  castings  had  been  exposed  for  some 
time  to  rain,  before  being  collected,  and  must  have 
.ost  some  weight  by  disintegration,  but  they  still  re- 
tained tV.rir  form 


3-8'; 


1-37 


162  WEIGHT   OF   EARTH  Chap.  Ill 

"Weight  of  the  Castings  accumulated  at  the  mouth 
OF  A  SINGLE  BuRROW — continued. 

Dunces. 
(6.)  The  heaviest  of  the  above  twelve  castings  ..        1*76 

(7.)  Lower  Bengal. — Avtiage  weight  of  22  castings,! 

collected  by  Mr.  J.  Scott,  and  stated  by  him  to  havei     1*24 
been  thrown  up  in  the  course  of  one  or  two  nights  ) 
(8.)  The  heaviest  of  the  above  22  castings    ..  ,.        2 '09 

(9.)  Nilgiri  Mountains,  S.  India  ;  average  weight  of^ 

the  5  largest  castings  collected  by  Dr.  King.    They  I     q.ik 
had  been  exposed  to  the  rain  of  the  last  monsoon,  j 
and  must  have  lost  some  weight      ..  ..  ..J 

(10.)  The  heaviest  of  the  above  5  castings     ..  ..       4"  34 

In  this  table  we  see  that  castings  which  had 
been  ejected  at  the  mouth  of  the  same  burrow, 
and  which  in  most  cases  appeared  fresh  and 
always  retained  their  vermiform  configuration, 
generally  exceeded  an  ounce  in  weight  after 
being  dried,  and  sometimes  nearly  equalled  a 
quarter  of  a  pound.  On  the  Nilgiri  moun- 
tains one  easting  even  exceeded  this  latter 
weight.  The  largest  castings  in  England 
were  found  on  extremely  poor  pasture- land ; 
and  these,  as  far  as  I  have  seen,  are  generally 
larger  than  those  on  land  producing  a  rich 
vegetation.  It  would  appear  that  worms 
];ave  to  swallow  a  greater  amount  of  earth 
0J1  poor  than  on  rich  land,  in  order  to  obtain 
Bufficient  nutriment. 

With    respect    to  the  tower-like   castings 


Chap.  III.        BROUGHT   UP   BY   WORMS.  163 

near  Nice  (Nos.  5  and  6  in  the  above  table)^ 
Dr.  King  often  found  five  or  six  of  them  on 
a  square  foot  of  surface  ;  and  these,  judging 
from  their  average  weight,  would  have 
weighted  together  7^  ounces ;  so  that  the 
weight  of  those  on  a  square  yard  would 
have  been  4  lb.  3 J  oz.  Dr.  King  collected, 
near  the  close  of  the  year  1872,  all  the 
castings  which  still  retained  their  vermiform 
shape,  whether  broken  down  or  not,  from  a 
square  foot,  in  a  place  abounding  with  worms, 
on  the  summit  of  a  bank,  where  no  castings 
could  have  rolled  down  from  above.  These 
castings  must  have  been  ejected,  as  he  judged 
from  their  appearance  in  reference  to  the 
rainy  and  dry  periods  near  Nice,  within  the 
previous  five  or  six  months  ;  they  weighed 
9^  oz.,  or  5  lb.  5^  oz.  per  square  yard.  After 
an  interval  of  four  months,  Dr.  King  collected 
all  the  castings  subsequently  ejected  on  the 
same  square  foot  of  surface,  and  they  weighed 
2^oz.,  or  lib.  6  J  oz.  per  square  yard. 
Therefore  within  about  ten  months,  or  we 
will  say  for  safety's  sake  within  a  year,  12  oz. 
of  castings  were  thrown  up  on  this  one 
square    foot,  or  6*75  pounds  on  the  square 


164  WEIGHT   OF   EARTH  Chap.  TIL 

yard  ;    and    tins  would  give  14*58  tons  per 
acre. 

In  a  field  at  the  bottom  of  a  valley  in  the 
chalk  (see  No.  2  in  the  foregoing  table),  a 
square  yard  was  measured  at  a  spot  where 
very  large  castings  abounded  ;  they  appeared, 
however,  almost  equally  numerous  in  a  few 
other  places.  These  castings,  which  retained 
perfectly  their  vermiform  shape,  were  col- 
lected ;  and  they  weighed  when  partially 
dried,  1  lb.  13^  oz.  This  field  had  been 
rolled  with  a  heavy  agricultural  roller  fifty-two 
days  before,  and  this  would  certainly  have 
flattened  every  single  casting  on  the  land. 
The  weather  had  been  very  dry  for  two  or 
three  weeks  before  the  day  of  collection,  so 
that  not  one  casting  appeared  fresh  or  had 
been  recently  ejected.  We  may  therefore 
assume  that  those  which  were  weighed  had 
been  ejected  within,  we  will  say,  forty  days 
from  the  time  when  the  field  was  rolled, — 
that  is,  twelve  days  short  of  the  whole  inter- 
vening period.  I  had  examined  the  same 
part  of  the  field  shortly  before  it  was  rolled, 
and  it  then  abounded  with  fresh  castings. 
Worms  do  not  work  in  dry  weather  during 


Chap.  III.        BKOUGIIT  UP    BY   WORMS.  165 

the  summer,  or  in  winter  during  severe  frosts. 
If  we  assume  that  they  work  for  only  half 
the  year — though  this  is  too  low  an  estimate 
' — then  the  worms  in  this  field  would  eject 
during  the  year,  8*387  pounds  per  square 
yard;  or  18'12  tons  per  acre,  assuming  the 
wdiole  surface  to  be  equally  productive  in 
castings. 

In  the  foregoing  cases  some  of  the 
necessary  data  had  to  be  estimated,  but  in 
the  two  following  cases  the  results  are  much 
more  trustworthy.  A  lady,  on  whose  ac- 
curacy I  can  implicitly  rely,  offered  to  collect 
during  a  year  all  the  castings  thrown  up  on 
two  separate  square  yards,  near  Leith  Hill 
Place,  in  Surrey.  The  amount  collected  was, 
however,  somewhat  less  than  that  originally 
ejected  by  the  worms ;  for,  as  I  have  repeatedly 
observed,  a  good  deal  of  the  finest  earth  is 
washed  away,  whenever  castings  are  thrown  up 
during  or  shortly  before  heavy  rain.  Small 
portions  also  adhered  to  the  surrounding 
blades  of  grass,  and  it  required  too  much 
time  to  detach  every  one  of  them.  On 
sandy  soil,  as  in  the  present  instance,  castings 
are  liable  to  crumble  after  dry  weather,  and 


163  WEIGHT   OF   EARTH  Chap.  IH 

particles  were  thus  o^ten  lost.  The  lady  also 
occasionally  left  home  for  a  week  or  iwo^  and 
at  such  times  the  castings  must  have  suffered 
still  greater  loss  from  exposure  to  the  weather. 
These  losses  were,  however,  compensated  to 
some  extent  by  the  collections  having  been 
made  on  one  of  the  squares  for  four  days,  and 
on  the  other  square  for  two  days  more  than 
the  year. 

A  space  was  selected  (October  9th,  1870) 
on  a  broad,  grass-covered  terrace,  which  had 
been  mowed  and  swept  during  many  years. 
It  faced  the  south,  but  was  shaded  during 
part  of  the  day  by  trees.  It  had  been 
formed  at  least  a  century  ago  by  a  great 
accumulation  of  small  and  large  fragments  of 
sandstone,  together  with  some  sandy  earth, 
rammed  down  level.  It  is  probable  that  it 
was  at  first  protected  by  being  covered  with 
turf.  This  terrace,  judging  from  the  number 
of  castings  on  it,  was  rather  unfavourable  for 
the  existence  of  worms,  in  comparison  with 
the  neighbouring  fields  and  an  upper  terrace. 
It  was  indeed  surprising  that  as  many  worms 
could  live  here  as  were  seen ;  for  on  digging 
a  hole   in   this   terrace,  the  black  vegetable 


Chap.  III.        BROUGHT   UP   BY   WORMS.  167 

mould  together  with  the  turf  was  ouly  four 
inches  in  thickness,  beneath  which  lay  the 
level  surface  of  light-coloured  sandy  soil,  with 
many  fragments  of  sandstone.  Before  any 
castings  were  collected  all  the  previously 
existing  ones  were  carefully  removed.  The 
last  day's  collection  was  on  October  14th, 
1871.  The  castings  were  then  well  dried 
before  a  fire  ;  and  they  weighed  exactly  3  J  lbs. 
This  would  give  for  an  acre  of  similar  land 
7*56  tons  of  dry  earth  annually  ejected  by 
worms. 

The  second  square  was  marked  on  un- 
enclosed common  land,  at  a  height  of  about 
700  ft.  above  the  sea,  at  some  little  distance 
from  Leith  Hill  Tower.  The  surface  was 
clothed  with  short,  fine  turf,  and  had  never 
been  disturbed  by  the  hand  of  man.  The 
spot  selected  appeared  neither  particularly 
favourable  nor  the  reverse  for  worms  ;  but  I 
have  often  noticed  that  castings  are  especially 
abundant  on  common  land,  and  this  may, 
perhaps,  be  attributed  to  the  poorness  of 
the  soil.  The  vegetable  mould  was  here 
between  three  and  four  inches  in  thickness. 
As  this  spot  was  at  some  distance  from  the 

12 


168  WEIGHT   OF   EARTH  Chap.  III. 

house  where  the  lady  lived,  the  castings  were 
not  collected  at  such  short  intervals  of  time 
as  those  on  the  terrace ;  consequently  the 
loss  of  fine  earth  during  rainy  weather  must 
have  been  greater  in  this  than  in  the  last 
case.  The  castings  moreover  were  more 
sandy,  and  in  collecting  them  during  dry 
weather  they  sometimes  crumbled  into  dust, 
and  much  was  thus  lost.  Therefore  it  is 
certain  that  the  worms  brought  up  to  the 
surface  considerably  more  earth  than  that 
which  was  collected.  The  last  collection 
was  made  on  October  27th,  1871  ;  i.e.,  367 
days  after  the  square  had  been  marked  out 
and  the  surface  cleared  of  all  pre-existing 
castings.  The  collected  castings,  after  being 
well  dried,  weighed  7*453  pounds;  and  this 
would  give,  for  an  acre  of  the  same  kind  of 
land,  16*1  tons  of  annually  ejected  dry  earth. 

Summary  of  the  four  foregoing  Cases. 

(1.)  Castings  ejected  near  Nice  within  about  a  year,  collected 
by  Dr.  King  on  a  square  foot  of  surface,  calculated  to  yield  per 
acre  14*58  tons. 

(2.)  Castings  ejected  during  aoout  45  days  on  a  square  yard, 
in  a  field  of  poor  pasture  at  the  bottom  of  a  large  valley  in  the 
Chalk,  calculated  to  yield  annually  per  acre  18*12  tons. 

(3.)  Castings  collected  from  a  square  yard  on  an  old  terrace  at 


Chap.  III.        BKOUGHT   UP  BY   WOEMS.  169 

Leith  Hill  Place,  during  369  days,  calculated  to  yield  annually 
per  acre  7 '  56  tons. 

(4.)  Castings  collected  from  a  square  yard  on  Leith  Hill 
Common  during  367  days,  calculated  to  yield  annually  per  acre 
16*1  tons. 

The  thickness  of  the  layer  of  mouldy  which 
castings  ejected  during  a  year  would  form  if 
uniformly  spread  out. — As  we  know  from 
the  two  last  cases  in  the  above  summary,  the 
weight  of  the  dried  castings  ejected  by  worms 
during  a  year  on  a  square  yard  of  surface,  I 
wished  to  learn  how  thick  a  layer  of  ordinary 
mould  this  amount  would  form  if  spread  uni- 
formly over  a  square  yard.  The  dry  castings 
were  therefore  broken  into  small  particles, 
and  whilst  being  placed  in  a  measure  were 
well  shaken  and  pressed  down.  Those  col- 
lected on  the  Terrace  amounted  to  124*77 
cubic  inches ;  and  this  amount,  if  spread  out 
over  a  square  yard,  would  make  a  layer 
•09612  inch  in  thickness.  Those  collected  on 
the  Common  amounted  to  197*56  cubic  inches, 
and  would  make  a  similar  layer  *1524  inch  in 
thickness. 

These  thicknesses  must,  however,  be  cor- 
rected, for  the  triturated  castings,  after  being 
well  shaken  down  and  pressed,  did  not  make 


170  THICKNESS   OF   THE   MOULD      Chap.  III. 

nearly  so  compact  a  mass  as  vegetable  mould, 
though  each  separate  particle  was  very 
compact.  Yet  mould  is  far  from  being  com- 
pact, as  is  shown  by  the  number  of  air- 
bubbles  which  rise  up  when  the  surface  is 
flooded  with  water.  It  is  moreover  pene- 
trated by  many  fine  roots.  To  ascertain  ap- 
proximately by  how  much  ordinary  vegetable 
mould  would  be  increased  in  bulk  by  beiiig 
broken  up  into  small  particles  and  then  dried, 
a  thin  oblong  block  of  somewhat  argillaceous 
mould  (with  the  turf  pared  off)  was  measured 
before  being  broken  up,  was  well  dried  and 
again  measured.  The  drying  caused  it  to 
shrink  by  ^  of  its  original  bulk,  judging  from 
exterior  measurements  alone.  It  was  then 
triturated  and  partly  reduced  to  powder,  in  the 
same  manner  as  the  castings  had  been  treated, 
and  its  bulk  now  exceeded  (notwithstanding 
shrinkage  from  drying)  by  -^  that  of  the 
original  block  of  damp  mould.  Therefore  the 
above  calculated  thickness  of  the  layer,  formed 
by  the  castings  from  the  Terrace,  after  being 
damped  and  spread  over  a  square  yard,  would 
have  to  be  reduced  by  yV»  ^^^^  ^^^^  ^^i^^ 
reduce  the  layer  to  '09  of  an  inch,  so  that  a 


Chap.  III.  ANNUALLY   ACCUMULATED.  171 

layer  '9  inch  in  thickness  would  be  formed  in 
the  course  of  ten  years.  On  the  same  prin- 
ciple the  castings  from  the  Common  would 
make  in  the  course  of  a  single  year  a  layer 
•1429  inch,  or  in  the  course  of  10  years  1'429 
inch,  in  thickness.  We  may  say  in  round 
numbers  that  the  thickness  in  the  former  case 
would  amount  to  nearly  1  inch,  and  in  the 
second  case  to  nearly  IJ  inch  in  10  years. 

In  order  to  compare  these  results  with 
those  deduced  from  the  rates  at  which  small 
objects  left  on  the  surfaces  of  grass  fields 
become  buried  (as  described  in  the  early  part 
of  this  chapter),  we  will  give  the  following 
summary : — 

BlTMMARY    OF    THE    THICKNESS    OF     THE    MoULD    ACCUMULATED 

OVER  Objects   left   strewed  on  the  Surface,  in  the 

COURSE   OF   TEN   YEARS. 

The  accumulation  of  mould  during  14|  years  on  the  surface 
of  a  dry,  sandy,  grass-field  near  Maer  Hall,  amounted  to  2*2 
inches  in  10  years. 

The  accumulation  during  21^  years  on  a  swampy  field  near 
Maer  Hall,  amounted  to  nearly  1*9  inch  in  10  years. 

The  accumulation  during  7  years  on  a  very  swampy  field  near 
Maer  Hall  amounted  to  2  •  1  inches  in  10  years. 

The  accumulation  during  29  years,  on  good,  argillaceous 
pasture-land  over  the  Chalk  at  Down,  amounted  to  2*2  inches  in 
10  years. 

The  accumulation  durmg  30  years  on  the  side  of  a  valley  over 


172  THICKNESS   OF   THE   MOULD      Chap.  III. 

the  Chalk  at  Down,  the  soil  being  argillaceous,  very  poor,  and 
only  just  converted  into  pasture  (so  that  it  was  for  some  years 
unfavourable  for  worms),  amounted  to  0*83  inches  in  10  years. 

In  these  cases  (excepting  the  last)  it  may 
be  seen  that  the  amount  of  earth  brouglit 
to  the  surface  during  10  years  is  somev^hat 
greater  than  that  calculated  from  the  castings 
which  were  actually  weighed.  This  excess 
may  be  partly  accounted  for  by  the  loss  which 
the  weighed  castings  had  previously  under- 
gone through  being  washed  by  rain,  by  the 
adhesion  of  particles  to  the  blades  of  the  sur- 
rounding grass,  and  by  their  crumbling  wlien 
dry.  Nor  must  we  overlook  other  agencies 
which  in  all  ordinary  cases  add  to  the 
amount  of  mould,  and  which  would  not  be 
included  in  the  castings  that  were  collected, 
namely,  the  fine  earth  brought  up  to  the 
surface  by  burrowing  larvge  and  insects,  espe- 
cially by  ants.  The  earth  brought  up  by  moles 
generally  has  a  somewhat  different  appearance 
from  vegetable  mould  ;  but  after  a  time  would 
not  be  distinguishable  from  it.  In  dry  coun- 
tiies,  moreover  the  wind  plays  an  important 
part  in  carrying  dust  from  one  place  to  another, 
and  even  in  England  it  must  add  to  the  mould 


Chap.  HI.         ANNUALLY   ACCUMULATED.  173 

on  fields  near  great  roads.  But  in  our  county 
these  latter  several  agencies  appear  to  be  of 
quite  subordinate  importance  in  comparison 
with  the  action  of  worms. 

We  have  no  means  of  judging  how  great  a 
weight  of  earth  a  single  full-sized  worm  ejects 
during  a  year.  Hensen  estimates  that  53,767 
worms  exist  in  an  acre  of  land;  but  this  is 
founded  on  the  number  found  in  gardens,  and 
he  believes  that  only  about  half  as  many  live 
in  corn-fields.  How  many  live  in  old  pasture 
land  is  unknown ;  but  if  we  assume  that  half 
the  above  number,  or  26,886  worms  live  on 
such  land,  then  taking  from  the  previous 
summary  15  tons  as  the  weight  of  the  castings 
annually  thrown  up  on  an  acre  of  land,  each 
worm  must  annually  eject  20  ounces.  A  fuli- 
sized  casting  at  the  mouth  of  a  single  burrow 
often  exceeds,  as  we  have  seen,  an  ounce  in 
weight ;  and  it  is  probable  that  worms  eject 
more  than  20  full-sized  castings  during  a 
year.  If  they  eject  annually  more  than  20 
ounces,  we  may  infer  that  the  worms  which 
live  in  an  acre  of  pasture  land  must  be  less 
than  26,886  in  number. 

Worms  live  chiefly  in  the  superficial  mould, 


174  THICKNESS   OF   THE   MOULD      Chap.  HI. 

which  is  usually  from  4  or  5  to  10  and  even 
1 2  inches  in  thickness ;  and  it  is  this  mould 
which  passes  over  and  over  again  through 
their  bodies  and  is  brought  to  the  surface. 
But  worms  occasionally  barrow  into  the  sub- 
soil to  a  much  greater  depth,  and  on  such 
occasions  they  bring  up  earth  from  this 
greater  depth ;  and  this  process  has  gone  on 
for  countless  ages.  Therefore  the  superficial 
layer  of  mould  would  ultimately  attain, 
though  at  a  slower  and  slower  rate,  a  thick- 
ness equal  to  the  depth  to  which  worms 
ever  burrow,  were  there  not  other  opposing 
agencies  at  work  which  carry  away  to  a 
lower  level  some  of  the  finest  earth  which  is 
continually  being  brought  to  the  surface  by 
worms.  How  great  a  thickness  vegetable 
mould  ever  attains,  I  have  not  had  good 
opportunities  for  observing;  but  in  the  next 
chapter,  when  we  consider  the  burial  of 
ancient  buildings,  some  facts  will  be  given  on 
this  head.  In  the  two  last  chapters  we 
shall  see  that  the  soil  is  actually  increased, 
though  only  to  a  small  degree,  through  the 
agency  of  worms;  but  their  chief  work  ia 
to  sift  the  finer  from  the  coarser  particles,  to 


Chap.  III.         ANNUALLY   ACCUMULATED.  175 

mingle  the  whole  with  vegetable  debris,  and 
to  saturate  it  with  their  intestinal  secretions. 

FinaJlj,  no  one  who  considers  the  facts 
given  in  this  chapter — on  the  burying  of 
small  objects  and  on  the  sinking  of  great 
stones  left  on  the  surface— on  the  vast 
number  of  worms  which  live  within  a 
moderate  extent  of  ground — on  the  weight  of 
the  castings  ejected  from  the  mouth  of  the 
same  burrow — on  the  weight  of  all  the  cast- 
ings ejected  within  a  known  time  on  a  measured 
space — will  hereafter,  as  I  believe,  doubt  that 
worms  play  an  important  part  in  nature. 


CHAPTER  IV. 

THE    PART    WHICH    WORMS    HAVE    PLATED    IX 
THE    BURIAL    OF    ANCIENT    BUILDINGS. 

The  accumulation  of  rubbisli  on  the  sites  of  great  cities  inde- 
pendent of  the  action  of  worms — The  burial  of  a  Roman  villa 
at  Abinger — The  floors  and  walls  penetrated  by  worms — 
Subsidence  of  a  modern  pavement — The  buried  pavement  at 
Beaulieu  Abbey — Roman  villas  at  Chedworth  and  Brading — 
The  remains  of  the  Roman  town  at  Silchester — The  nature  of 
the  debris  by  which  the  remains  are  covered — The  penetration 
of  the  tesselated  floors  and  walls  by  worms — Subsidence  of 
the  floors — Thickness  of  the  mould — The  old  Roman  city  of 
Wroxeter — Thickness  of  the  mould — Depth  of  the  foundations 
of  some  of  the  Buildings — Conclusion. 

Archaeologists  are  probably  not  aware  how 
much  tbey  ow'G  to  worms  for  the  preservation 
of  many  ancient  objects.  Coins,  gold  orna- 
ments, stone  implements,  &c.,  if  dropped  on 
the  surface  of  the  ground,  will  infallibly  be 
buried  by  the  castings  of  worms  in  a  few 
years,  and  w^ill  thus  be  safely  preserved,  until 
the  land  at  some  future  time  is  turned  up 
For  instance,  many  years  ago  a   grass-field 


Chap.  IY.         OF   ANCIENT   BUILDINGS.  177 

was  ploughed  on  the  northern  side  of  the 
Severn,  not  far  from  Shrewsbury ;  and  a 
surprising  number  of  iron  arrow-heads  were 
found  at  the  bottom  of  the  furrows_,  which,  as 
Mr.  Blakeway,  a  local  antiquary,  believed, 
were  relics  of  the  battle  of  Shrewsbury  in  the 
year  1403,  and  no  doubt  had  been  originally 
left  strewed  on  the  battle-field.  In  the 
present  chapter  I  shall  show  that  not  only 
implements,  &c.,  are  thus  preserved,  but  that 
the  floors  and  the  remains  of  many  ancient 
buildings  in  England  have  been  buried  so 
effectually,  in  large  part  through  the  action 
of  worms,  that  they  have  been  discovered  in 
recent  times  solely  through  various  accidents. 
The  enormous  beds  of  rubbish,  several  yards 
in  thickness,  which  underlie  many  cities, 
such  as  Rome,  Paris,  and  London,  the  lower 
ones  being  of  great  antiquity,  are  not  here 
referred  to,  as  they  have  not  been  in  any 
way  acted  on  by  worms.  When  we  con- 
sider how  much  matter  is  daily  brought  into 
a  great  city  for  building,  fuel,  clothing  and 
food,  and  that  in  old  times  when  the  roads 
were  bad  and  the  work  of  the  scavenger 
was  neglected,  a  comparatively  small  amount 


178  BURIAL   OF   THE   REMAINS       Chap.  IV 

was  carried  away,  we  may  agree  with 
Elie  de  Beaumont,  who,  in  discussing  this 
subject,  says,  "  pour  une  voiture  de  materiaux 
"  qui  en  sort,  on  y  en  fait  entrer  cent."  *  Nor 
should  we  overlook  the  effects  of  fires,  the 
demolition  of  old  buildings^  and  the  removal 
of  rubbish  to  the  nearest  vacant  space. 

Abinger,  Surrey, — Late  in  the  autumn  of 
1876,  the  ground  in  an  old  farm-yard  at  this 
place  was  dug  to  a  depth  of  2  to  2|  feet,  and 
the  workmen  found  various  ancient  remains. 
This  led  Mr.  T.  H.  Farrer  of  Abinger  Hall  to 
have  an  adjoining  ploughed  field  searched. 
On  a  trench  being  dug,  a  layer  of  concrete, 
still  partly  covered  with  tesserae  (small  red 
tiles),  and  surrounded  on  two  sides  by  broken- 
down  walls,  was  soon  discovered.  It  is 
believed  f  that  this  room  formed  part  of  the 
atrium  or  reception-room  of  a  Roman  villa. 
The  walls  of  two  or  three  other  small  rooms 
were  afterwards  discovered.  Many  fragments 
of  pottery,  other  objects,  and  coins  of  several 


•  *  Le9ons  de  G^ologie  pratique,'  1845,  p.  142. 

\  A  short  account  of  this  discovery  was  published  in  *  The 
Times'  of  January  2,  1878;  and  a  fuller  account  in  *  The 
Builder,'  January  5,  1878. 


Chap.  IV.         OF   ANCIENT   BUILDINGS.  179 

Roman  emperors,  datiug  from  133  to  361,  and 
perhaps  to  375  A.D.,  were  likewise  found. 
-Also  a  half-penny  of  George  1.,  1715.  The 
presence  of  this  latter  coin  seems  an  anomaly  ; 
but  no  doubt  it  was  dropped  on  the  ground 
during  the  last  century,  and  since  then  there 
has  been  ample  time  for  its  burial  under  a 
considerable  depth  of  the  castings  of  worms. 
From  the  different  dates  of  the  Roman  coins 
we  may  infer  that  the  building  was  long 
inhabited.  It  was  probably  ruined  and 
deserted  1400  or  1500  years  ago. 

I  was  present  during  the  commencement  of 
the  excavations  (August  20,  1877)  and  Mr. 
Farrer  had  two  deep  trenches  dug  at  opposite 
ends  of  the  atrium,  so  that  I  might  examine- 
the  nature  of  the  soil  near  the  remains. 
The  field  sloped  from  east  to  west  at  an  angle 
of  about  7° ;  and  one  of  the  two  trenches, 
shown  in  the  accompanying  section  (Fig.  8) 
was  at  the  upper  or  eastern  end.  The 
diagram  is  on  a  scale  of  -^q  of  an  inch  to  an 
inch  ;  but  the  trench,  which  was  between  4 
and  5  feet  broad,  and  in  parts  above  5  feet 
deep,  has  necessarily  been  reduced  out  of  all 
proportion.      The  fine  mould  over  the  floor 


180 


BURIAL   OF   THE   REMAINS       Chap.  IV. 


Section  throngli  the  foundations  of  a  buried  Roman  yilla  at 
Abinger.  A  A,  vegetable  mould  ;  B,  dark  earth  full  of  stones, 
]3  inches  in  thickness  ;  C,  black  mould  ;  D,  broken  morfar  ; 
E,  black  mould  ;  F  F,  undisturbed  sub-soil ;  G,  tesserse  ;  H. 
concrete     I,  nature  unknown  ;  W,  buried  wall. 


Chap.  IV.         OF   ANCIENT   BUILDINGS.  181 

of  the  atrium  varied  in  thickness  from  11 
to  16  inches;  and  on  the  side  of  the  trench  in 
the  section  was  a  little  over  1 3  inches.  After 
the  mould  had  been  removed,  the  floor 
appeared  as  a  whole  moderately  level ;  but  it 
sloped  in  parts  at  an  angle  of  1°,  and  in  one 
place  near  the  outside  at  as  much  as  8°  30'* 
The  wall  surrounding  the  pavement  was 
built  of  rough  stones,  and  was  23  inches  in 
thickness  where  the  trench  w^as  dug.  Its 
broken  summit  was  here  13  inches,  but  in 
another  part  15  inches,  beneath  the  surface  of 
the  field,  being  covered  by  this  thickness  of 
mould.  In  one  spot,  however,  it  rose  to 
within  6  inches  of  the  surface.  On  two 
sides  of  the  room,  where  the  junction  of  the 
concrete  floor  with  the  bounding  walls  could 
be  carefully  examined,  there  was  no  crack  or 
separation.  This  trench  afterwards  proved 
to  have  been  dug  within  an  adjoining  room 
(11  ft.  by  11  ft.  6  in.  in  size),  the  existence  of 
which  was  not  even  suspected  whilst  I  was 
present. 

On  the  side  of  the  trench  farthest  from  the 
buried  wall  (W),  the  mould  varied  from  9  to 
14  inches  in  thickness;  it  rested  on  a  mass  (B'^ 


182  BURIAL   OF   THE   REMAINS       Chap.  IY. 

23  inches  thick  of  blackish  earth,  including 
many  large  stones.  Beneath  this  was  a  thin 
bed  of  very  black  mould  (C),  then  a  layer  of 
earth  full  of  fragments  of  mortar  (D),  and 
then  another  thin  bed  (about  3  inches  thick) 
(F)  of  very  black  mould,  which  rested  on  the 
undisturbed  subsoil  (F)  of  firm,  yellowish, 
argillaceous  sand.  The  23-inch  bed  (B)  was 
probably  made  ground,  as  this  would  have 
brought  up  the  floor  of  the  room  to  a  level 
with  that  of  the  atrium.  The  two  thin  beds 
of  black  mould  at  the  bottom  of  the  trench 
evidently  marked  two  former  land-surfaces. 
Outside  the  walls  of  the  northern  room,  many 
bones,  ashes,  oyster-shells,  broken  pottery  and 
an  entire  pot  were  subsequently  found  at  a 
depth  of  16  inches  beneath  the  surface. 

The  second  trench  was  dug  on  the  western 
or  lower  side  of  the  villa :  the  mould  was 
here  only  6|-  inches  in  thickness,  and  it 
rested  on  a  mass  of  fine  earth  full  of  stones, 
broken  tiles  and  fragments  of  mortar,  34 
inches  in  thickness,  beneath  which  was  the 
undisturbed  sand.  Most  of  this  earth  had 
probably  been  washed  down  from  the  upper 
part    of    the    field,   and    the    fragments    of 


CuAP.  IV  OF   ANCIEKT   BUILDINGS.  IS.S 

stones,  tiles,  &c.,  must  have  come  from  the 
immediately  adjoining  ruins. 

It  appears  at  first  sight  a  surprising  fact 
that  this  field  of  light  sandy  soil  should  haxe 
been  cultivated  and  ploughed  during  many 
years,  and  that  not  a  vestige  of  these  buildings 
should  have  been  discovered.  No  one  even 
suspected  that  the  remains  of  a  Roman 
villa  lay  hidden  close  beneath  the  surface. 
But  the  fact  is  less  surprising  when  it  is 
known  that  the  field,  as  the  bailiff  believed, 
had  never  been  ploughed  to  a  greater  depth 
than  4  inches.  It  is  certain  that  when  the 
land  was  first  ploughed,  the  pavement  and 
the  surrounding  broken  walls  must  have  been 
covered  by  at  least  4  inches  of  soil,  for  other- 
wise the  rotten  concrete  floor  would  have 
been  scored  by  the  ploughshare,  the  tesserae 
torn  up,  and  the  tops  of  the  old  walls 
knocked  down. 

When  the  concrete  and  tesseras  were  first 
cleared  over  a  space  of  14  by  9  ft.,  the  floor 
which  was  coated  with  trodden-down  earth 
exhibited  no  signs  of  having  been  penetrated 
by  worms ;  and  although  the  overlying  fine 
mould  closelv  resembled  that  which  in  many 

13 


184  BURIAL   OF   THE   REMAINS       Chap.  IV 

places  has  certainly  been  accumulated  bj 
worms,  yet  it  seemed  hardly  possible  that  this 
mould  could  have  been  brought  up  by  wormp 
from  beneath  the  apparently  sound  floor.  It 
seemed  also  extremely  improbable  that  the 
thick  walls,  surrounding  the  room  and  still 
united  to  the  concrete,  had  been  undermined 
by  worms,  and  had  thus  been  caused  to  sink, 
being  afterwards  covered  up  by  their  cast- 
ings. I  therefore  at  first  concluded  that  all 
the  fine  mould  above  the  ruins  had  been 
washed  down  from  the  upper  parts  of  the 
field  ;  but  we  shall  soon  see  that  this  conclu- 
sion was  certainly  erroneous,  though  much 
fine  earth  is  known  to  be  washed  down  from 
the  upper  part  of  the  field  in  its  present 
ploughed  state  during  heavy  rains. 

Although  the  concrete  floor  did  not  at 
first  appear  to  have  been  anywhere  pene- 
trated by  worms,  yet  by  the  next  morning 
little  cakes  of  the  trodden-down  earth  had 
been  lifted  up  by  worms  over  the  mouths  of 
seven  burrows,  which  passed  thi-ough  tho 
softer  parts  of  the  naked  concrete,  or  between 
the  interstices  of  the  tesserge.  On  the  third 
morning  twen+y-five  burrows  were  counted ; 


Chap.  IV.  OF   ANCIENT    BUILDINGS.  185 

and  hj  suddenly  lifting  up  the  little  cakes  of 
earth,  four  worms  were  seen  in  the  act 
of  quickly  retreating.  Two  castings  were 
thrown  up  during  the  third  night  on  the 
floor,  and  these  were  of  large  size.  The 
season  was  not  favourable  for  the  full  activity 
of  worms,  and  the  weather  had  lately  been 
Lot  and  dry,  so  that  most  of  the  worms  now 
lived  at  a  considerable  depth.  In  digging 
the  two  trenches  many  open  burrows  and 
some  worms  were  encountered  at  between 
30  and  40  inches  beneath  the  surface  ;  but  at 
a  greater  depth  they  became  rare.  One 
worm,  however,  was  cut  through  at  48|,  and 
another  at  51^  inches  beneath  the  surface. 
A  fresh  humus-lined  burrow  was  also  met 
with  at  a  depth  of  57  and  another  at  Gfi^ 
inches.  At  greater  depths  than  this,  neither 
burrows  nor  worms  were  seen. 

As  I  wished  to  learn  how  many  worms 
lived  beneath  the  floor  of  the  atrium — a 
space  of  about  14  by  9  feet — Mr.  Farrer 
was  so  kind  as  to  make  observations  for 
me,  during  the  next  seven  weeks,  by  which 
time  the  worms  in  the  surrounding  country 
were    in     full     activity,    and    were    work- 


186  BUKIAL   OF   THE   REMAINS       Cha?.  TY 

ing  near  the  surface.  It  is  very  improbable 
that  worms  should  have  migrated  from  the 
adjoining  field  into  the  small  space  of  the 
atrium,  after  the  superficial  mould  in  which 
they  prefer  to  live,  had  been  removed.  We 
may  therefore  conclude  that  the  burrows  and 
the  castings  which  were  seen  here  during  the 
ensuing  seven  weeks  were  tlie  work  of  the 
former  inhabitants  of  the  space.  I  will  now 
give  a  few  extracts  from  Mr.  Farrer's  notes. 

Aug.  2'jth,  1877;  that  is,  five  days  after 
the  floor  had  been  cleared.  On  the  previous 
night  there  had  been  some  heavy  rain,  which 
washed  the  surface  clean,  and  now  the  mouths 
of  forty  burrows  were  counted.  Parts  of  the 
concrete  were  seen  to  be  solid,  and  had  never 
been  penetrated  by  worms,  and  here  the  rain- 
water lodged. 

Sept.  5th. — Tracks  of  worms,  made  during 
the  previous  night,  could  be  seen  on  the  sur- 
face of  the  floor,  and  five  or  six  vermiform 
castings  had  been  thrown  up.  These  were 
defaced. 

Sept.  12th. — During  the  last  six  days,  the 
worms  have  not  been  active,  though  many 
castings  have  been  ejected  in  the  neighbour 


Chap.  IV.  OF   ANCIENT   BUILDINGS.  187 

ins:  fields  ;  but  on  tliis  day  the  earth  was  a 
little  raised  over  the  mouths  of  the  burrows, 
or  castings  were  ejected,  at  ten  fresh  points. 
These  were  defaced.  It  should  be  understood 
that  wdien  a  fresh  barrow  is  sjDoken  of,  this 
generally  means  only  that  an  old  burrow  has 
been  re-opened.  Mr.  Farrer  was  repeatedly 
struck  with  the  pertinacity  with  which  the 
worms  re-opened  their  old  burrows,  even  w^hen 
no  earth  was  ejected  from  them.  I  have 
often  observed  the  same  fact,  and  generally 
the  mouths  of  the  burrows  are  protected  by 
an  accumulation  of  pebbles,  sticks  or  leaves. 
Mr.  Farrer  likewise  observed  that  the  worms 
living  beneath  the  floor  of  the  atrium  often 
collected  coarse  grains  of  sand,  and  such  httle 
stones  as  they  could  find,  round  the  mouths 
of  their  burrows. 

Sept.  13th  ;  soft  wet  weather.  The  mouths 
of  the  burrows  were  re-opened,  or  castings 
were  ejected,  at  31  points;  these  w^ere  all 
defaced. 

Sept.    14th ;    34    fresh    holes    or   castings 
all  defaced. 

Sept.  15th  ;  44  fresh  holes,  only  5  castings  ; 
ail  defaced. 


188  BUEIAL   OF   THE   REMAINS         Chap.  IV. 

Sept.  18tb  ;  43  fresli  holes,  8  castings;  all 
defaced. 

The  number  of  castings  on  the  surrounding 
fields  was  now  very  large. 

Sept.  19t]i  ;  40  holes,  8  castings;  all 
defaced. 

Sept.  22nd  ;  43  holes,  only  a  few  fresh 
castings ;  all  defaced. 

Sept.  23rd ;  44  holes,  8  castings. 

Sept.  25th ;  50  holes,  no  record  of  the 
number  of  castings. 

Oct.  13th ;  61  holes,  no  record  of  the 
number  of  castings. 

After  an  interval  of  three  years,  Mr.  Farrer, 
at  my  request,  again  looked  at  the  concrete 
floor,  and  found  the  worms  still  at  work. 

Knowing  what  great  muscular  power  worms 
possess,  and  seeing  how  soft  the  concrete  was 
in  many  parts,  I  was  not  surprised  at  its 
having  been  penetrated  by  their  burrows ; 
but  it  is  a  more  surprising  fact  that  the 
mortar  between  the  rough  stones  of  the  thick 
walls,  surrounding  the  rooms,  was  found  by 
Mr.  Farrer  to.  have  been  penetrated  by  worms. 
On  August  26th,  that  is,  Rve  days  after  the 
ruins    had    been    exposed,   he    observed    four 


Chap.  IV.         OF  ANCIENT   BUILDINGS.  189 

open  burrows  on  the  broken  summit  of  the 
eastern  wall  (W  in  Fig.  8) ;  and,  on  Septem- 
ber 15th,  other  burrows  similarly  situated 
were  seen.  It  should  also  be  noted  that  in 
the  perpendicular  side  of  the  trench  (which 
was  much  deeper  than  is  represented  in 
Fig.  8)  three  recent  burrows  were  seen,  which 
ran  obliquely  far  down  beneath  the  base  of 
the  old  wall. 

AYe  thus  see  that  many  worms  lived  beneath 
the  floor  and  the  walls  of  the  atrium  at  the 
time  when  the  excavations  were  made ;  and 
that  they  afterwards  almost  daily  brought  up 
earth  to  the  surface  from  a  considerable 
depth.  There  is  not  the  slightest  reason  to 
doubt  that  worms  have  acted  in  this  manner 
ever  since  the  period  when  the  concrete  wa?< 
su£6.ciently  decayed  to  allow  them  to  penetrate 
it ;  and  even  before  that  period  they  would 
have  lived  beneath  the  floor,  as  soon  as  it 
became  pervious  to  rain,  so  that  the  so  1 
beneath  was  kept  damp.  The  floor  and  the 
walls  must  therefore  have  been  continually 
undermined ;  and  fine  earth  must  have  been 
heaped  on  them  during  many  centuries, 
perhaps  for  a  thousand  years.    If  the  burrows 


190  BUEIAL   OF   THE   EEMAINS       Chap.  IV 

beneath  the  floor  and  walls,  which  it  is  prob- 
able were  formerly  as  numerous  as  they  now 
are,  had  not  collapsed  in  the  course  of  time 
in  the  manner  formerly  explained,  the  under- 
lying earth  would  have  been  riddled  with  pas- 
sages like  a  sponge ;  and  as  this  was  not 
the  case,  we  may  feel  sure  that  thev  have 
collapsed.  The  inevitable  result  of  such  col- 
lapsing during  successive  centuries,  will  have 
been  the  slow  subsidence  of  the  floor  and  of  the 
walls,  and  their  burial  beneath  the  accumu- 
lated worm-castings.  The  subsidence  of  a 
floor,  whilst  it  still  remains  nearly  horizontal, 
may  at  first  appear  improbable  ;  but  the  case 
presents  no  more  real  difficulty  than  that  of 
loose  objects  strewed  on  the  surface  of  a  field, 
which,  as  we  have  seen,  become  buried  several 
inches  beneath  the  surface  in  the  course  of  a 
few  years,  though  still  forming  a  horizontal 
layer  parallel  to  the  surface.  The  burial  of 
the  paved  and  level  path  on  my  lawn,  which 
took  place  under  my  own  observation,  is  an 
analogous  case.  Even  those  parts  of  the 
concrete  floor  which  the  worms  could  not 
penetrate  would  almost  certainly  have  been 
imdermined,  and  would  have  sunk,  like  the  great 


Chap.  IV.         OF   ANCIENT   BUILDINGS.  191 

stones  at  Leith  Hill  Place  and  Stonehenge, 
for  the  soil  would  have  been  damp  beneath 
them.  But  the  rate  of  sinking  of  the  dif- 
ferent parts  would  not  have  been  quite  equal, 
and  the  floor  was  not  quite  level.  The 
foundations  of  the  boundary  walls  lie,  as 
shown  in  the  section,  at  a  very  small  depth 
beneath  the  surface ;  they  would  therefore 
have  tended  to  subside  at  nearly  the  same 
rate  as  the  floor.  But  this  would  not  have 
occurred  if  the  foundations  had  been  deep, 
as  in  the  case  of  some  other  Roman  ruins 
presently  to  be  described. 

Finally,  we  may  infer  that  a  large  part  of 
the  fine  vegetable  mould,  which  covered  the 
floor  and  the  broken-down  walls  of  this  villa, 
in  some  places  to  a  thickness  of  16  inches, 
was  brought  up  from  below  by  worms.  P'rom 
facts  hereafter  to  be  given  there  can  be  no 
doubt  that  some  of  the  finest  earth  thus 
brought  up  will  have  been  washed  down  the 
sloping  surface  of  the  field  during  every  heavy 
shower  of  rain.  If  this  had  not  occurred  a 
greater  amount  of  mould  would  have  accumu- 
lated over  the  ruins  than  that  now  present. 
But  beside  the  castings  of  worms  and  some 


192  BURIAL   OF   THE   REMAINS       Chap.  IV 

earth  brought  up  by  iDsects,  and  some  accu- 
mulation of  dust,  much  fine  earth  will  have 
been  washed  over  the  ruins  from  the  upper 
parts  of  the  field,  since  it  has  been  under 
cultivation  ;  and  from  over  the  ruins  to  the 
lower  parts  of  the  slope  ;  the  present  thick- 
ness of  the  mould  being  the  resultant  of  these 
several  agencies. 

I  may  here  append  a  modern  instance  of 
the  sinking  of  a  pavement,  communicated  to 
me  in  1871  by  Mr.  Ramsay,  Director  of  the 
Geological  Survey  of  England.  A  passage 
without  a  roof,  7  feet  in  length  by  3  feet  2 
inches  in  width,  led  from  his  house  into  the 
garden,  and  was  paved  with  slabs  of  Portland 
stone.  Several  of  these  slabs  were  16  inches 
square,  others  larger,  and  some  a  little  smaller. 
This  pavement  had  subsided  about  3  inches 
along  the  middle  of  the  passage,  and  two 
inches  on  each  side,  as  could  be  seen  by  the 
lines  of  cement  by  which  the  slabs  had  been 
originally  joined  to  the  walls.  The  pave- 
ment had  thus  become  slightly  concave  along 
the  middle ;  but  there  w^as  no  subsidence  at 
the  end  close  to  the   house.      Mr.  Ramsaj^ 


Chap.  IV.  OF   ANCIENT   BUILDINGS.  193 

could  not  account  for  this  sinking,  until  he 
observed  that  castings  of  black  mould  were 
frequently  ejected  along  the  lines  of  junction 
between  the  slabs ;  and  these  castings  were 
regularly  swept  away.  The  several  lines  of 
junction,  including  those  with  the  lateral 
walls,  were  altogether  39  feet  2  inches  in 
length.  The  pavement  did  not  present  the 
appearance  of  ever  having  been  renewed, 
and  the  house  was  believed  to  have  been 
built  about  eighty-seven  years  ago.  Con- 
sidering all  these  circumstances,  Mr.  Ramsay 
does  not  doubt  that  the  earth  brought  up  by 
the  worms  since  the  pavement  was  first  laid 
down,  or  rather  since  the  decay  of  the  mortar 
allowed  the  worms  to  burrow  through  it,  and 
therefore  within  a  much  shorter  time  than 
the  eighty-seven  years,  has  sufficed  to  cause  the 
sinking  of  the  pavement  to  the  above  amount, 
except  close  to  the  house,  where  the  ground 
beneath  would  have  been  kept  nearly  dry. 

Beaulieu  Abbey,  Hampshire. — This  abbey 
was  destroyed  by  Henry  YIIl.,  and  there 
now  remains  only  a  portion  of  the  southern 
aisle-wall.  It  is  believed  that  the  king  had 
mobt  of  the  stones  carried  away  for  building 


194  BUEIAL   OF   THE   REMAINS       Chap.  IV 

a  castle ;  and  it  is  certain  tliat  they  have  been 
removed.  The  position  of  the  nave-transept 
was  ascertained  not  long  ago  by  the 
foundations  having  been  found  ;  and  the 
|)lace  is  now  marked  by  stones  let  into 
the  ground.  Where  the  abbey  formerly 
stood,  there  now  extends  a  smooth  grass- 
covered  surface,  which  resembles  in  all 
respects  the  rest  of  the  field.  The  guardian, 
a  very  old  man,  said  the  surface  had  never 
been  levelled  in  his  time.  In  the  year  1853, 
the  Duke  of  Buccleuch  had  three  holes  dug 
in  the  turf  within  a  few  yards  of  one  another, 
at  the  western  end  of  the  nave ;  and  the  old 
tesselated  pavement  of  the  abbey  was  thus 
discovered.  These  holes  were  afterwards 
surrounded  by  brickwork,  and  protected  by 
trap-doors,  so  that  the  pavement  might  be 
readily  inspected  and  preserved.  When  my 
son  William  examined  the  place  on  January 
5,  1872,  he  found  that  the  pavement  in  the 
three  holes  lay  at  depths  of  6|,  10  and  Hi 
laches  beneath  the  surrounding  turf-covered 
surface.  The  old  guardian  asserted  that  he 
was  often  forced  to  remove  worni'Castings 
from  the  23avement ;    and  that  he  had  done 


Chap.  IV.  OF    ANCIENT    BUILDINGS.  195 

SO  about  six  montlis  before.  My  son  collected 
all  from  one  of  the  holes,  the  area  of  which 
was  5*32  square  feet,  and  they  weighed  '7*97 
ounces.  Assuming  that  this  amount  ha.l 
accumulated  in  six  months,  the  accumulation 
during  a  year  on  a  square  yard  would  be 
1'68  pounds,  which,  though  a  large  amount, 
is  very  small  compared  with  wliat,  as  we 
have  seen,  is  often  ejected  on  fields  and 
commons.  When  I  visited  the  abbey  on 
June  22,  1877,  the  old  man  said  that  he  had 
cleared  out  the  holes  about  a  month  before, 
but  a  good  many  castings  had  since  been 
ejected.  I  suspect  that  he  imagined  that  he 
swept  the  pavements  oftener  than  he  really 
did,  for  the  conditions  were  in  several  re- 
spects very  unfavourable  for  the  accumulation 
of  even  a  moderate  amount  of  castings.  The 
tiles  are  rather  large,  viz.,  about  5i  inches 
square,  and  the  mortar  between  them  was  in 
most  places  sound,  so  that  the  worms  were 
able  to  bring  up  earth  from  below  only  at 
certain  points.  The  tiles  rested  on  a  bed  of 
concrete,  and  the  castings  in  consequence  con- 
sisted in  large  part  (viz.,  in  the  proportion 
of  19  to  33)  of  particles  of  mortar,  grains  of 


19(3  BURIAL   OF   THE   REMAINS       Chap.  IV. 

sand,  little  fragments  of  rock,  bricks  or  tile ; 
and  such  substances  could  hardly  be  agreeable, 
and  certainly  not  nutritious,  to  worms. 

My  son  dug  holes  in  several  places  within 
the  former  walls  of  the  abbey,  at  a  distance  of 
several  yards  from  the  above  described 
bricked  squares.  He  did  not  find  any  tiles, 
though  these  are  known  to  occur  in  some 
other  parts,  but  he  came  in  one  spot  to  con- 
crete on  which  tiles  had  once  rested.  The 
fine  mould  beneath  the  turf  on  the  sides  of 
the  several  holes,  varied  in  thickness  from 
only  2  to  2  J  inches,  and  this  rested  on  a  layer 
from  8  a  to  above  11  inches  in  thickness, 
consisting  of  fragments  of  mortar  and  stone- 
rubbish  with  the  interstices  compactly  filled 
up  with  black  mould.  In  the  surrounding 
field,  at  a  distance  of  20  yards  from  the 
abbey,  the  fine  vegetable  mould  was  11  inches 
thick. 

We  may  conclude  from  these  facts  that 
when  the  abbey  was  destroyed  and  the  stones 
removed,  a  layer  of  rubbish  was  left  over  the 
whole  surface,  and  that  as  soon  as  the  worms 
were  able  to  penetrate  the  decayed  concrete 
and  the  joints  between  the  tiles,  they  slowly 


Chap.  IV.         OF   ANCIENT   BUILDINGS.  197 

filled  up  the  interstices  in  the  overlying 
rubbish  with  their  castings,  which  were  after- 
wards accumulated  to  a  thickness  of  nearly 
three  inches  over  the  whole  surface.  If  we 
add  to  this  latter  amount  the  mould  between 
tlje  fragments  of  stones,  some  five  or  six 
inches  of  mould  must  have  been  brought  up 
from  beneath  the  concrete  or  tiles.  The  con- 
crete or  tiles  will  consequently  have  subsided 
to  nearly  this  amount.  The  bases  of  the 
columns  of  the  aisles  are  now  buried  beneath 
mould  and  turf.  It  is  not  probable  that 
they  can  have  been  undermined  by  worms, 
for  their  foundations  would  no  doubt  have 
been  laid  at  a  considerable  depth.  If  they 
have  not  subsided,  the  stones  of  which  the 
columns  were  constructed  must  have  been 
removed  from  beneath  the  former  level  of 
the  floor. 

Chedu:orth^  Gloucestershire, — The  remains 
of  a  large  Roman  villa  were  discovered  here 
in  1866,  on  ground  which  had  been  covered 
with  wood  from  time  immemorial.  No 
suspicion  seems  ever  to  have  been  enter- 
tained that  ancient  buildings  lay  buried  here, 
until   a  gamekeeper,  in  digging  for  rabbits, 


198  BURIAL    OF   THE    REMAINS        Chap.  IV. 

encountered  some  remains.*  But  subse- 
quently the  tops  of  some  stone  walls  were  de- 
tected in  parts  of  the  wood,  projecting  a  little 
above  the  surface  of  the  ground.  Most  of  the 
coins  found  here  belonged  to  Constans  (who 
died  350  a.d.)  and  the  Constant! ne  family. 
My  sons  Francis  and  Horace  visited  the 
place  in  November  1877,  for  tlie  sake  of 
ascertaining  what  part  worms  may  have 
played  in  the  burial  of  these  extensive  re- 
mains. Bat  the  circumstances  were  not 
favourable  for  this  object,  as  the  ruins  are  sur- 
rounded on  three  sides  by  rather  steep  banks, 
do^vn  which  earth  is  washed  during  rainy 
weather.  Moreover  most  of  the  old  rooms 
have  been  covered  with  roofs,  for  the  pro- 
tection of  the  elegant  tesselated  pavements. 

A  few  facts  may,  however,  be  given  on  the 
thickness  of  the  soil  over  these  ruins.  Close 
outside  the  northern  rooms  there  is  a  broken 
wall,  the  summit  of  which  was  covered  by  5 

*  Several  accounts  of  these  ruins  have  been  published  ;  the 
Dest  is  by  Mr.  James  Farrer  in  '  Proc.  Soc.  of  Antiquaries  of 
Scotland,'  vol.  vi,,  Part  II.,  1867,  p.  278.  Also  J,  W.  Grover, 
'Journal  of  the  British  Arch.  Assoc'  June  1866.  Professor 
nuckman  has  likewise  published  a  pamphlet,  *  Notes  on  the 
Rtimau  Villa  at  Chcdwcrth,'  2nd  edit.  1873:  Cirencester. 


Chap.  IV.  OF   ANCIENT   BUILDINOS.  199 

inches  of  black  mould ;  and  in  a  hole  dug  on 
the  outer  side  of  this  wall,  where  the  ground 
had  never  before  been  disturbed,  black  mould, 
full  of  stones,  26  inches  in  thickness,  v^m 
found,  resting  on  the  undisturbed  sub- soil  oi 
yellow  clay.  At  a  depth  of  22  inches  from 
the  surface  a  pig's  jaw  and  a  fragment  of  a 
tile  were  found.  When  the  excavations  were 
first  made,  some  large  trees  grew  over  the 
ruins ;  and  the  stump  of  one  has  been  left 
directly  over  a  party-wall  near  the  bath  room, 
for  the  sake  of  showing  the  thickness  of  the 
superincumbent  soil,  which  was  here  38 
inches.  In  one  small  room,  which,  after 
being  cleared  out,  had  not  been  roofed  over, 
my  sons  observed  the  hole  of  a  worm  passing 
through  the  rotten  concrete,  and  a  living 
worm  was  found  within  the  concrete.  In 
another  open  room  worm-castings  were  seen 
on  the  floor,  over  which  some  earth  had  by 
this  means  been  deposited,  and  here  grass 
now  grew. 

JBrading,  Isle  of  Wight. — A  fine  Roman 
villa  was  discovered  here  in  1880  ;  and  by 
the  end  of  October  no  less  than  18  chambers 
Mad  been  more  or  less  clenrud.      A  coin  dated 

14 


200  BURIAL   OF   THE   REMAINS       Chap.  IV. 

337  A.D.  was  found.  My  son  William  visited 
the  place  before  the  excavations  were  com- 
pleted ;  and  he  informs  me  that  most  of  tho 
floors  were  at  first  covered  with  much  rubbish 
and  fallen  stones,  having  their  interstices 
completely  filled  up  with  mould,  abounding 
as  the  workmen  said,  with  worms,  above 
which  there  was  mould  without  any  stones. 
The  whole  mass  was  in  most  places  from  3 
to  above  4  ft.  in  thickness.  In  one  very 
large  room  the  overlying  earth  was  only 
2  ft.  6  in.  thick  ;  and  after  this  had  been  re- 
moved, so  many  castings  were  thrown  up 
between  the  tiles  that  the  surface  had  to 
be  almost  daily  swept.  Most  of  the  floors 
were  fairly  level.  The  tops  of  the  broken- 
down  walls  were  covered  in  some  places  by 
only  4  or  5  inches  of  soil,  so  that  they  were 
occasionally  struck  by  the  plough,  but  in 
other  places  they  were  covered  by  from  13 
to  18  inches  of  soil.  It  is  not  probable  that 
these  walls  could  have  been  undermined  by 
worms  and  subsided,  as  they  rested  on  a 
foundation  of  very  hard  red  sand,  into  which 
worms  could  hardly  burrow.  The  mortar, 
however,  between  the  stones  of  the  walls  of 


Chap.  IV.  OF   ANCIENT   BUILDINGS.  201 

a  hypocaust  was  found  by  my  son  to  have 
been  penetrated  by  many  worm-burrows. 
The  remains  of  this  villa  stand  on  land  which 
slopes  at  an  angle  of  about  3° ;  and  the  land 
appears  to  have  been  long  cultivated.  There- 
fore no  doubt  a  considerable  quantity  of  fine 
earth  has  been  washed  down  from  the  upper 
parts  of  the  field,  and  has  largely  aided  in 
the  burial  of  these  remains. 

Silchester,  Hampshire. — The  ruins  of  this 
small  Roman  town  have  been  better  pre- 
served than  any  other  remains  of  the  kind 
in  England.  A  broken  wall,  in  most  parts 
from  15  to  18  feet  in  height  and  about  1^ 
mile  in  compass,  now  surrounds  a  space  of 
about  100  acres  of  cultivated  land,  on  which 
a  farm-house  and  a  church  stand.*  Formerly, 
when  the  weather  was  dry,  the  lines  of  the 
buried  walls  could  be  traced  by  the  appear- 
ance of  the  crops  ;  and  recently  very  exten- 
sive excavations  have  been  undertaken  by 
the  Duke  of  Wellington,  under  the  superin- 
tendence of  the  late  Kev.  J.  Gr.  Joyce,  by 
which  means  many  large  buildings  have  been 

*  These  details  are  taken  from  the  *  Penny  Encyclopa3dia, 
article,  Hampshire. 


202  BURIAL   OF   THE    REMAINS       Chap.  IV 

discovered.  Mr.  Joyce  made  careful  coloured 
sections,  and  measured  the  thickness  of  each 
bed  of  rubbish,  whilst  the  excavations  were  in 
progress ;  and  he  has  had  the  kindness  to 
send  me  copies  of  several  of  them.  When 
my  sons  Francis  and  Horace  visited  these 
ruins^  he  accompanied  them,  and  added  his 
notes  to  theirs. 

Mr.  Joyce  estimates  that  the  town  was  in- 
habited by  the  Romans  for  about  three  cen- 
turies ;  and  no  doubt  much  matter  must  have 
accumulated  wnthin  the  walls  during  this  long 
period.  It  appears  to  have  been  destroyed 
by  fire,  and  most  of  the  stones  used  in  the 
buildings  have  since  been  carried  away. 
These  circumstances  are  unfavourable  for  as- 
certaining the  part  which  w^orms  have  played 
in  the  burial  of  the  ruins;  but  as  careful 
sections  of  the  rubbish  overlying  an  ancient 
town  have  seldom  or  never  before  been  made 
in  England,  I  will  give  copies  of  the  most 
characteristic  portions  of  some  of  those  made 
by  Mr.  Joyce.  They  are  of  too  great  length 
to  be  here  introduced  entire. 

An  east  and  west  section,  30  ft.  in  length, 
was  made  across  a  room  in  the  Basilica,  now 


Chap.  IV.  OF   ANCIENT   BUILDINGS. 


203 


called  the  Hall  of  the  Merchants  (Fig.  9). 
The  hard  concrete  floor,  still  covered  here 
and  there  with  tesserae,  was  found  at  3  ft» 


Fig.  9. 
Section  within  a  room  in  the  Basilica  at  SilcLester.     Scale  ^. 


204  BURIAL   OF   THE   REMAINS       Chap.  IV. 

beneath  the  surface  of  the  field,  which  was 
here  leveL  On  the  floor  there  were  two 
large  piles  of  charred  wood,  one  alone  of 
which  is  shown  in  the  part  of  the  section 
here  given.  This  pile  w^as  covered  by  a  thin 
white  layer  of  decayed  stucco  or  plaster, 
above  which  was  a  mass,  presenting  a  singu- 
larly disturbed  appearance,  of  broken  tiles, 
mortar,  rubbish  and  fine  gravel,  together  27 
inches  in  thickness.  Mr.  Joyce  believes  that 
the  gravel  was  used  in  making  the  mortar 
or  concrete,  which  has  since  decayed,  some 
of  the  lime  probably  having  been  dissolved. 
The  disturbed  state  of  the  rubbish  may  have 
been  due  to  its  having  been  searched  for 
building  stones.  This  bed  was  capped  by 
fine  vegetable  mould,  9  inches  in  thickness. 
From  these  facts  we  may  conclude  that  the 
Hall  was  burnt  down,  and  that  much  rubbish 
fell  on  the  floor,  through  and  from  which  the 
worms  slowly  brought  up  the  mould,  now 
forming  the  surface  of  the  level  field. 

A  section  across  the  middle  of  another  hall 
in  th3  Basilica,  32  feet  6  inches  in  length, 
called  the  (Evarium,  is  shown  in  Fig.  10. 
It  appears  that  we  have  here  evidence  of  twc 


CUAP.   IV. 


OF  ANCIENT   BUILDINGS. 


205 


fires,  separated  by  an  interval  of  time,  during 
which  the  6  inches  of  "  mortar  and  concrete 


Ms  .2 


^    6  03 


F  \i 


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■    If^ 

■^cpI^*| 

I  ^^f4 

■  ^  K 

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■  V/l       ^Klk  a/S^ 

^    KB^iffi^ 

Fig.  10. 
Section  within  a  hall  in  the  Basilica  at  Silchester.     Scale  3^- 


206  BURIAL   OF   THE    REMAINS       Chap.  IV. 

with  broken  tiles  "  was  accumulated.  Be- 
neath one  of  the  layers  of  charred  wood,  a 
vahiable  rehc,  a  bronze  eagle,  was  found ; 
and  this  shows  that  the  soldiers  must  have 
deserted  the  pkce  in  a  panic.  Owing  to  the 
death  of  Mr.  Joyce,  I  have  not  been  able  to 
ascertain  beneath  which  of  the  two  layers  the 
eagle  was  found.  The  bed  of  rubble  overly- 
ing the  undisturbed  gravel  originally  formed, 
as  I  suppose,  the  floor,  for  it  stands  on  a  level 
with  that  of  a  corridor,  outside  the  walls  of 
the  Hall;  but  the  corridor  is  not  shown  in  the 
section  as  here  given.  The  vegetable  mould 
was  16  inches  thick  in  the  thickest  part;  and 
the  depth  from  the  surface  of  the  field,  clothed 
with  herbage,  to  the  undisturbed  gravel,  was 
40  inches. 

The  section  shown  in  Fig.  11  represents  an 
excavation  made  in  the  middle  of  the  town, 
and  is  here  introduced  because  the  bed  of  "  rich 
"mould"  attained,  according  to  Mr.  Joyce,  the 
unusual  thickness  of  20  inches.  Gravel  lay 
at  the  depth  of  48  inches  from  the  surface 
but  it  was  not  ascertained  whether  this  was 
in  its  natural  state,  or  had  been  brought  here 
and  had  been  rammed  down,  as  occurs  in 
some  other  places. 


Chap.  IV.  OF   ANCIENT   BUILDINGS. 


207 


The  section  shown  in  Fig.  12  was  taken 
in  the  centre  of  the  Basilica,  and  though  it  was 
5  feet  in  depth,  the  natural  sub-soil  was  not 


Mould,      20      inches 
thick. 


Rubble  wi'h    broken 
t.les,  4  inches  thick. 


Black  decayed  wood, 
in  th.ckfi~t  pait  6 
inches  thick. 


Fig.  11. 

Section  in  a  block  of  buildings  in  the  middle  of  the  town  of 
Silchester. 


reached.  The  bed  marked  ""  concrete  "  was 
probably  at  one  time  a  floor ;  and  the  beds 
beneath  seem  to  be  the  remnants  of  more 
ancient  buildings.     The  vegetable  mould  was 


208 


BURIAL   OF   THE   REMAINS       Chap.  IV. 


here   only    9    inches   thick.     In  some   other 
sections,     not     copied,     we     likewise     have 


im^  ^'^ 


- —    1  Mould,  9  inches  thick. 


%:^ 


Ligh'-coloured  earth  with 
large  pitces  of  broken 
tiles,  7  inches. 


Dai  k,  fine  grained  rubbish 
with  small  bits  oi  tiles 
20  inches. 


Concrete,  4  inches. 
Stucco,  2  inches. 


Made  bottom   with   frag- 
ments of  tiles,  8  ibches. 


Fine-grained  made  ground, 
with  the  debrii  of  older 
buildings. 


Fig.  12. 
Section  in  the  centre  of  the  Basilica  at  Silchester. 


evidence   of  buildings  having  been   erected 
over  the  ruins  of  older  ones.     In   one  case 


Chap.  IV.  OF   ANCIENT   BUILDINGS.  200 

there  was  a  layer  of  yellow  clay  of  very 
unequal  thickness  between  two  beds  of  debris, 
the  lower  one  of  which  rested  on  a  floor  with 
tesserse.  The  old  broken  walls  appear  some- 
times to  have  been  roughly  cut  down  to  a 
uniform  level,  so  as  to  serve  as  the  founda- 
tions of  a  temporary  building  ;  and  iMr.  Joyce 
suspects  that  some  of  these  buildings  were 
wattled  sheds,  plastered  with  clay,  which 
would  account  for  the  above-mentioned  layer 
of  clay. 

Turning  now  to  the  points  which  more 
immediately  concern  us.  Worm-castings 
were  observed  on  the  floors  of  several  of  the 
rooms,  in  one  of  which  the  tesselation  was 
unusually  perfect.  The  tesserye  here  con- 
sisted of  little  cubes  of  hard  sandstone  of 
about  1  inch,  several  of  which  were  loose 
or  projected  slightly  above  the  general  level 
One  or  occasionally  two  open  worm-burrows 
were  found  beneath  all  the  loose  tesserye. 
Worms  have  also  penetrated  the  old  walls  of 
these  ruins.  A  wall,  which  had  just  been 
exposed  to  view  during  the  excavations  then 
in  progress,  was  examined  :  it  was  built  of 
lar^e  flints,  and  was  18  inches  in  thickness. 


210  BURIAL   OF   THE   REMAINS       Chap.  IV 

It  appeared  sound,  but  when  the  soil  was 
removed  from  beneath,  the  mortar  in  the 
lower  part  was  found  to  be  so  much  decayed 
that  the  flints  fell  apart  from  their  own 
weight.  Here,  in  the  middle  of  the  wall,  at 
a  depth  of  29  inches  beneath  the  old  floor  and 
of  49  J  inches  beneath  the  surface  of  the  field, 
a  living  worm  was  found,  and  the  mortar  was 
penetrated  by  several  burrows. 

A  second  wall  was  exposed  to  view  for  the 
first  time,  and  an  open  burrow  was  seen  on 
its  broken  summit.  By  separating  the  flints 
this  burrow  was  traced  far  down  in  the 
interior  of  the  wall ;  but  as  some  of  the  flints 
cohered  firmly,  the  whole  mass  was  disturbed 
in  pulling  down  the  wall,  and  the  burrow 
could  not  be  traced  to  the  bottom.  The 
foundations  of  a  third  wall,  which  appeared 
quite  sound,  lay  at  a  depth  of  4  feet  beneath 
one  of  the  floors,  and  of  course  at  a  con- 
siderably greater  depth  beneath  the  level  of 
the  ground.  A  large  flint  was  wrenched  out 
of  the  wall  at  about  a  foot  from  the  base, 
and  this  required  much  force,  as  the  mortar 
was  sound ;  but  behind  the  flint  in  the 
middle  of  the  wall,  the  mortar  was  friable, 


Chap.  IV.         OF   ANCIENT   BUILDINGS.  213. 

and  here  there  were  worm-burrows.  Mr. 
Joyce  and  my  sons  were  surprised  at  the 
blackness  of  the  mortar  in  this  and  in  several 
other  cases,  and  at  the  presence  of  mould  in 
the  interior  of  the  walls.  Some  may  have 
been  placed  there  by  the  old  builders  instea  1 
of  mortar ;  but  we  sliould  remember  that 
worms  line  their  burrows  with  black  humus. 
Moreover  open  spaces  would  almost  certainly 
have  been  occasionally  left  between  the  large 
irregular  flints  ;  and  these  spaces,  we  may 
feel  sure,  would  be  filled  up  by  the  worms 
witb  their  castings,  as  soon  as  they  were  able 
to  penetrate  the  wall.  Rain-water,  oozing 
down  the  burrows  would  also  carry  fine 
dark-coloured  particles  into  every  crevice. 
Mr.  Joyce  was  at  first  very  sceptical  about 
the  amount  of  work  which  I  attributed  to 
worms  ;  but  he  ends  his  notes  with  reference 
to  the  last-mentioned  wall  by  saying,  "  This 
"  case  caused  me  more  surprise  and  brought 
*'  more  conviction  to  me  than  any  other.  I 
"  should  have  said,  and  did  say,  that  it  was 
'' quite  impossible  such  a  wall  could  have  been 
'*  penetrated  by  earth-worms." 

In  almost  all  the  rooms  the  pavement  has 


212 


BUKIAL   OF   THE   EEMAINS       Chap.  IV. 


ui 


CO       'T^ 

^.     > 
to     ^ 


fe 


sunk  considerably,  especi- 
ally towards  the  middle ; 
and  this  is  shown  in  the 
three  following  sections. 
The  measurements  were 
made  by  stretching  a  string 
tightly  and  horizontally 
over  the  floor.  The  sec- 
tion, Fig.  13,  was  taken 
from  north  to  south  across 
a  room,  18  feet  4  incVies  in 
length,  with  a  nearly  per- 
fect pavement,  next  to  the 
"Red  Wooden  Hut."  In 
the  northern  half,  the  sub- 
sidence amounted  to  5|: 
inches  beneath  the  level  of 
the  floor  as  it  now  stands 
close  to  the  walls;  and  it 
was  greater  in  the  northern 
than  in  the  southern  half ; 
but,  according  to  Mr.  Joyce, 
the  entire  pavement  has 
obviously  subsided.  In 
several  places,  the  tessera3 
appeared  as  if  drawn  a  little 
away  from  the  walls  ;  whilst 


Chap.  IV.  OF   ANCIENT   BUILDINGS.  213 

in  other  places  tliey  were  still  in  close  contact 
with  them. 

In  Fig.  14^  we  see  a  section  across  tlie 
paved  floor  of  the  southern  corridor  or 
ambulatory  of  a  quadrangle,  in  an  excavation 
made  near  *'  The  Spring."  The  floor  is  7 
feet  9  inches  wide,  and  the  broken-down 
walls  now  project  only  |  of  an  inch  above  its 
level.  The  field,  which  was  in  pasture,  here 
sloped  from  north  to  south,  at  an  angle 
of  3°  40'.  The  nature  of  the  ground  on  each 
side  of  the  corridor  is  shown  in  the  section. 
It  consisted  of  earth  full  of  stones  and  other 
debris,  capped  with  dark  vegetable  mould 
which  was  thicker  on  the  lower  or  southern 
than  on  the  northern  side.  The  pavemeni 
was  nearly  level  along  lines  parallel  to  the 
side-walls,  but  had  sunk  in  the  middle  as 
much  as  7f  inches. 

A  small  room  at  no  great  distance  from  that 
represented  in  Fig.  13,  had  been  enlarged  by 
the  Roman  occupier  on  the  southern  side,  by 
an  addition  of  5  feet  4  inches  in  breadth.  For 
this  purpose  the  southern  wall  of  the  house  had 
been  pulled  down,  but  the  foundations  of  the 
old  wall  had  been  left  buried  at  a  little  depth 


214 


BURIAL   OF    THE   REMAINS       Chap,  IY 


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Chap.  IV.  OF   ANCIENT   BUILDINGS.  215 

beneath  the  pavement  of  the  enlarged  room. 
Mr.  Jojce  beheves  that  this  buried  wall  must 
have  been  built  before  the  reign  of  Claudius  IT., 
who  died  270,  a.d.  We  see  in  the  accom 
panying  section,  Fig.  15,  that  the  tesselated 
pavement  has  subsided  to  a  less  degree  over  the 
buried  wall  than  elsewhere  ;  so  that  a  slight 
convexity  or  protuberance  here  stretched  in  a 
straight  line  across  the  room.  This  led  to 
a  hole  being  dug,  and  the  buried  wall  was 
thus  discovered. 

We  see  in  these  three  sections,  and  in 
several  others  not  given,  that  the  old  pave- 
ments have  sunk  or  sagged  considerably. 
Mr.  Joyce  formerly  attributed  this  sinking 
solely  to  the  slow  settling  of  the  ground. 
That  there  has  been  some  settling  is  highly 
probable,  and  it  may  be  seen  in  section  15 
that  the  pavement  for  a  width  of  5  feet 
over  the  southern  enlargement  of  the 
room,  which  must  have  been  built  on  fresh 
ground,  has  sunk  a  little  more  than  on  the 
old  northern  side.  But  this  sinking  may 
possibly  have  had  no  connection  with  the 
enlargement  of  the  room,  for  in  Fig.  13, 
one  half  of  the  pavement  has  subsided  more 

15 


216 


BURIAL   OF   THE   REMAINS        Chap.  IV. 


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Chap.  IV.  OF    ANCIENT   BUILDINGS.  217 

than  the  other  half  without  any  assignable 
cause.  In  a  bricked  passage  to  Mr.  Joyce's 
own  house,  laid  dowm  only  about  six  year8 
ago,  the  same  kind  of  sinking  has  occurred  as 
in  the  ancient  buildings.  Nevertheless  it  does 
not  appear  probable  that  the  whole  amount 
of  sinking  can  be  thus  accounted  for.  The 
Eoraan  builders  excavated  the  ground  to  an 
unusual  depth  for  the  foundations  of  their 
walls,  which  were  thick  and  solid ;  it  is 
therefore  hardly  credible  that  they  should 
have  been  careless  about  the  solidity  of  the 
bed  on  which  their  tesselated  and  often 
ornamented  pavements  were  laid.  The  sink- 
ing must,  as  it  appears  to  me,  be  attributed 
in  chief  part  to  the  pavement  having  been 
undermined  by  worms,  which  w^e  know  are 
still  at  work.  Even  Mr.  Joyce  at  last  ad- 
mitted that  this  could  not  have  failed  to  have 
produced  a  considerable  effect.  Thus  also  the 
large  quantity  of  fine  mould  overlying  the 
pavements  can  be  accounted  for,  the  presence 
of  w'hich  would  otherwise  be  inexplicable.  My 
sons  noticed  that  in  one  room  in  which  the 
pavement  had  sagged  very  little,  there  was  an 
unusually  small  amount  of  overlying  mould. 


218  BURIAL   OF   THE   REMAINS       Chap.  IV 

As  tlie  foundations  of  the  walls  generally 
He  at  a  considerable  depth,  they  will  either 
have  not  subsided  at  all  through  the  under- 
mining action  of  worms,  or  they  will  have 
subsided  much  less  than  the  floor.  This 
latter  result  would  follow  from  worms  not 
often  working  deep  down  beneath  the  founda- 
tions ;  but  more  especially  from  the  walls  not 
yielding  when  penetrated  by  worms,  whereas 
the  successively  formed  burrows  in  a  mass 
of  earth,  equal  to  one  of  the  walls  in  depth 
and  thickness,  would  have  collapsed  many 
times  since  the  desertion  of  the  ruins, 
and  would  consequently  have  shrunk  or 
subsided.  As  the  walls  cannot  have  sunk 
much  or  at  all,  the  immediately  adjoining 
pavement  from  adhering  to  them  will  have 
been  prevented  from  subsiding ;  and  thus 
the  present  curvature  of  the  pavement  is 
intelligible. 

The  circumstance  which  has  surprised  me 
most  with  respect  to  Silehester  is  that  during 
the  many  centuries  which  have  elapsed  since 
the  old  buildings  were  deserted,  the  vegetable 
mould  has  not  accumulated  over  them  to  a 
greater  thickness  than  that  here  observed.    In 


Chap.  IV.  OF   ANCIENT   BUILDINGS.  219 

most  places  it  is  only  about  9  inches  in  thick- 
ness, but  in  some  places  12  or  even  more 
inches.  In  Fig.  11,  it  is  given  as  20  inches, 
but  this  section  was  drawn  by  Mr.  Joyce 
before  his  attention  was  particularly  called  to 
this  subject.  The  land  enclosed  within  the 
old  walls  is  described  as  sloping  slightly  to 
the  south ;  but  there  are  parts  which,  accord- 
ing to  Mr.  Joyce,  are  nearly  level,  and  it 
appears  that  the  mould  is  here  generally 
thicker  than  elsewhere.  The  surface  slopes 
in  other  pai'ts  from  west  to  east,  and  Mr.  Joyce 
describes  one  floor  as  covered  at  the  western 
end  by  rubbish  and  mould  to  a  thickness 
of  28^  inches,  and  at  the  eastern  end  by  a 
thickness  of  only  11^  inches.  A  very  slight 
slope  suffices  to  cause  recent  castings  to  flow 
downwards  during  heavy  rain,  and  thus  much 
earth  will  ultimately  reach  the  neighbouring 
rills  and  streams  and  be  carried  away.  By 
this  means,  the  absence  of  very  thick  beds  of 
mould  over  these  ancient  ruins  may,  as  ] 
believe,  be  explained.  Moreover  most  of  the 
J  and  here  has  long  been  ploughed,  and  this 
would  greatly  aid  the  washing  away  of  the 
finer  earth  during  rainy  weather. 


220  BURIAL   OF   THE   REMAINS       Chap.  I^*. 

The  nature  of  tbe  beds  immediately 
beneath  the  vegetable  mould  in  some  of  the 
sections  is  rather  perplexing.  We  see,  for 
instance,  in  the  section  of  an  excavation  in  a 
grass  meadow  (Fig.  14),  which  sloped  from 
north  to  south  at  an  angle  of  3°  40',  that  the 
mould  on  the  upper  side  is  only  six  inches 
and  on  the  lower  side  nine  inches  in  thick- 
ness. But  this  mould  lies  on  a  mass  (2 5 J 
inches  in  thickness  on  the  upper  side)  "  of 
''  dark  brown  mould,"  as  described  by  Mr. 
Joyce,  "  thickly  interspersed  with  small 
"  pebbles  and  bits  of  tiles,  which  present  a 
"  corroded  or  worn  appearance."  The  state 
of  this  dark-coloured  earth  is  like  that  of  a 
field  which  has  long  been  ploughed,  for  the 
earth  thus  becomes  intermingled  with  stones 
and  fragments  of  all  kinds  which  have  been 
much  exposed  to  the  weather.  If  during  the 
course  of  many  centuries  this  grass  meadow 
and  the  other  now  cultivated  fields  have  been 
at  times  ploughed,  and  at  other  times  left  as 
pasture,  the  nature  of  the  ground  in  the  above 
section  is  rendered  intelligible.  For  worms 
will  continually  have  brought  up  fine  earth 
from   below,   which    will   have   been    stirred 


Ceap.  1Y.         of   ancient   BUILDINGS.  221 

up  by  the  plough  whenever  the  land  was 
cultivated.  But  after  a  time  a  greater 
thickness  of  fine  earth  will  thus  have  been 
accumulated  than  could  be  reached  by  the 
plough;  and  a  bed  like  the  25^-inch  mass, 
in  Fig.  14,  will  have  been  formed  beneath 
the  superficial  mould,  which  latter  will  have 
been  brought  to  the  surface  within  more 
recent  times,  and  have  been  well  sifted  by 
the  worms. 

JVroxeter,  Shropshire. — The  old  Roman  city 
of  Uriconium  was  founded  in  the  early  part 
of  the  second  century,  if  not  before  this  date ; 
and  it  was  destroyed,  according  to  Mr. 
Wright,  probably  between  the  middle  of  the 
fourth  and  fifth  century.  The  inhabitants 
were  massacred,  and  skeletons  of  women 
were  found  in  the  hypocausts.  Before  the 
year  1859,  the  sole  remnant  of  the  city  above 
ground,  was  a  portion  of  a  massive  wall 
about  20  ft.  in  height.  The  surrounding 
land  undulates  slightly,  and  has  long  been 
under  cultivation.  It  had  been  noticed  that 
the  corn-crops  ripened  prematurely  in  certain 
narrow  lines,  and  that  the  snow  remained  un- 
melted  in  certain  places  longer  than  in  others 


222  BURIAL   OF   THE   REMAINS       Chap.  IV. 

These  appearances  led,  as  I  was  informed,  to 
extensive  excavations  being  undertaken.  The 
foundations  of  many  large  buildings  and 
several  streets  have  thus  been  exposed  to  view. 
The  space  enclosed  within  the  old  walls  is 
an  irregular  oval,  about  1|  mile  in  length. 
Many  of  the  stones  or  bricks  used  in  the 
buildings  must  have  been  carried  away ;  but 
the  hyjDocausts,  baths,  and  other  underground 
buildings  were  found  tolerably  perfect,  being 
filled  with  stones,  broken  tiles,  rubbish  and 
soil.  The  old  floors  of  various  rooms  were 
covered  with  rubble.  As  I  was  anxious  to 
know  how  thick  the  mantle  of  mould  and 
rubbish  was,  which  had  so  long  concealed 
these  ruins,  I  applied  to  Dr.  H.  Johnson,  who 
had  superintended  tlie  excavations ;  and  he, 
with  the  greatest  kindness,  twice  visited  the 
place  to  examine  it  in  reference  to  ray  ques- 
tions, and  had  many  trenches  dug  in  four 
fields  which  had  hitherto  been  undisturbed. 
The  results  of  his  observations  are  given  in 
the  following  Table.  He  also  sent  me  speci- 
mens of  the  mould,  and  answered,  as  far  ay 
he  could,  all  my  questions. 


Chap.  IV.         OF   ANCIENT   BUILDINGS.  223 


Measurements  by  Dr.  H.  Johnson  of  the  thickness  of 
the  vegetable  mould  over  the  roman  ruins  at 
Wroxeteu. 

Trenches  dug  in  a  field  called  "  Old  Works." 

Thlcknf^ss 

of  mould  in 

inches. 

1.  At  a  depth  of  36  inches  undisturbed  sand  was 

reached  ..  ..  ..  ..  ..      20 

2.  At  a  depth  of  33  inches  concrete  was  reached  21 
o.         „         „         9  inches  concrete  was  reached        9 

Trenches  dug  in  a  field  called  '^Shop 
"Leasows  ;"  this  is  the  highest  field  within  the 
old  walls,  and  slopes  down  from  a  sub-central 
[^oint  on  all  sides  at  about  an  angle  of  2°. 

Thickness 

of  mould  in 

inches. 

4.  Summit  of  field,  trench  45  inches  deep  ..     40 

5.  Close  to  summit  of  field,  trench  36  inches  deep     26 

6.  „  „  trench  28  inches  deep    28 

7.  Near  summit  of  field,  trench  36  inches  deep        24 

8.  „  „  trench  at  one  end  89 
inches  deep  ;  the  mould  here  graduated  into 
tho  underlying  undisturbed  sand,  and  its 
thickness  is  somewhat  arbitrary.  At  the 
other  end  of  the  trench,  a  causeway  was  en- 
countered at  a  depth  of  only  7  inches,  and 

the  mould  was  here  only  7  inches  thick     ..  24 

9.  Trench  close  to  the  last,  28  inches  in  depth  ..  15 
iO  Lower  part  of  same  field,  trench  30  inches  deep  15 
11  „  „  trench  31  inches  deep  17 
12.              „             „             trench  36  inches  deep, 

at  which  depth  undisturbed  sand  was  reached     28 


221  BUKIAL   OF   THE   REMAINS       Chap.  IV 

Thickneg«i 

of  mould  in 

Inches. 

13.  In  another  part  of  same  field,  trench  9.^  inches 

deep,  stopped  by  concrete     ..  ..  .,       9  2 

14.  In  another  part  of  same  field,  trench  9  inches 

deep,  stopped  by  concrete     ..  ..  ..       9 

15.  In  another  part  of  the  same  field,  trench  24 

inches  deep,  when  sand  was  reached  ..      16 

16.  In  another  part  of  same  field,  trench  30  inches 

deep,  when  stones  were  reached  ;  at  one  end 
of  the  trench  mould  12  inches,  at  the  other 
end  14  inches  thick   ..  ..  ..  ..13 

Small  field  between  "Old  Works"  and 
*'  Shop  Leasows,"  I  believe  nearly  as  high  as 
the  upper  part  of  the  latter  field. 

Thickness 

of  mould  in 

inches. 

17.  Trench  26  inches  deep  ..  ..  ..     24 

18.  „      10  inches  deep,  and  then  came  U]ion  a 
causeway        ..  ..  ..  ..  ..10 

19.  Trench  34  inches  deep  ..  ..    ,      ..      30 

20.  „      31  inches  deep '  ..     31 

Field  on  the  western  side  of  the  space 
enclosed  within  the  old  walls. 

Thickness 

of  mould  in 

inches 

21.  Trench  28  inches  deep,  when  undisturbed  sand 

w^as  reached    ..  ..  ..  ..  ..     16 

22.  Trench  29  inches  deep,  when  undisturbed  sand 

was  reached    ..  ..  ..  ..  ..15 

23.  Trench  14  inches  dee}>,  and  then  came  upon  j* 

building  .,  ..  ..  .,  ..14 

Dr.  Johnson  distinguished  as  mould  the 
earth  which  differed,  more  or  less  abruptly,  in 


Chap.  IV.  OF    ANCIENT   BUILDINGS.  225 

its  dark  colour  and  in  its  texture  from  the 
underlying  sand  or  rubble.  In  the  specimens 
sent  to  me,  the  mould  resembled  that  which 
lies  immediately  beneath  the  turf  in  old 
pasture-land,  excepting  that  it  often  contained 
small  stones,  too  large  to  have  passed  through 
the  bodies  of  worms.  But  the  trenches  above 
described  were  dug  in  fields,  none  of  which 
were  in  pasture,  and  all  had  been  long- 
cultivated.  Bearing  in  mind  the  remarks 
made  in  reference  to  Silchester  on  the  effects 
of  long-continued  culture,  combined  with  the 
action  of  worms  in  bringing  up  the  finer 
particles  to  the  surface,  the  mould,  as  so 
designated  by  Dr.  Johnson,  seems  fairly  well 
to  deserve  its  name.  Its  thickness,  where 
there  was  no  causeway,  floor  or  walls  beneath, 
was  greater  than  has  been  elsewhere  ob- 
served, namely  in  many  places  above  2  ft., 
and  in  one  spot  above  3  ft.  The  mould  was 
thickest  on  and  close  to  the  nearly  level  sum- 
mit  of  the  field  called  "  Shop  Leasows,"  and 
in  a  small  adjoining  field,  which,  as  I  believe, 
is  of  nearly  the  same  height.  One  side  of 
the  former  field  slopes  at  an  angle  of  rather 
above  2°,  and  I  should    have  expected    that 


226  BURIAL   OF   THE   REMAINS       Chap.  IV 

the  mould,  from  being  washed  down  during 
heavy  rain,  would  have  been  thicker  in  the 
lower  than  in  the  upper  part;  but  this  was 
not  the  case  in  two  out  of  the  three  trenches 
here  dug. 

In  many  places,  where  streets  ran  beneatV 
the  surface,  or  where  old  buildings  stood,  the 
mould  was  only  8  inches  in  thickness;  and 
Dr.  Johnson  was  surprised  that  in  ploughing 
the  land,  the  ruins  had  never  been  struck  by 
the  plough  as  far  as  he  had  heard.  He  thinks 
that  when  the  land  was  first  cultivated  the  old 
walls  were  perhaps  intentionally  pulled  down, 
and  that  hollow  places  were  filled  up.  This 
may  have  been  the  case ;  but  if  after  the 
desertion  of  the  city  the  land  was  left  for 
many  centuries  uncultivated,  worms  would 
have  brought  up  enough  fine  earth  to  have 
covered  the  ruins  completely  ;  that  is  it 
they  had  subsided  from  having  been  under- 
mined. The  foundations  of  some  of  the  walls, 
for  instance  those  of  the  portion  still  stand- 
ing about  20  feet  above  the  ground,  and 
those  of  the  market-place,  lie  at  the  extra- 
ordinary depth  of  14  feet;  but  it  is  highly 
improbable  that  the  foundations  were  o^ener- 


Chap.  IV.         OP   ANCIENT   BUILDINGS.  227 

ally  SO  deep.  The  mortar  employed  in  the 
buildings  must  have  been  excellent,  for  it 
is  still  in  parts  extremely  hard.  Where- 
ever  walls  of  any  height  have  been  exposed 
to  view,  they  are,  as  Dr.  Johnson  believes, 
still  perpendicular.  The  walls  with  such 
deep  foundations  cannot  have  been  under- 
mined by  worms,  and  therefore  cannot  have 
subsided,  as  appears  to  have  occurred  at 
Abinger  and  Silchester.  Hence  it  is  very 
difficult  to  account  for  their  being  now  com- 
pletely covered  with  earth;  but  how  much 
of  this  covering  consists  of  vegetable  mould 
and  how  much  of  rubble  I  do  not  know. 
The  market-place,  with  the  foundations  at  a 
depth  of  14  feet,  was  covered  up,  as  Dr. 
Johnson  believes,  by  between  6  and  24  inches 
of  earth.  The  tops  of  the  broken-down  walls 
of  a  caldarium  or  bath,  9  feet  in  depth,  were 
likewise  covered  up  with  nearly  2  feet  of 
earth.  The  summit  of  an  arch,  leading  into 
an  ash-pit  7  feet  in  depth,  was  covered  up 
with  not  more  than  8  inches  of  earth.  When- 
ever a  building  which  has  not  subsided  is 
covered  with  earth,  w^e  must  suppose,  either 
that  the  upper  layers  of  stone  have  been  at 


228  BUKIAL   OF   THE   EEMAINS       Chap.  IV. 

some  time  carried  away  by  man,  or  that  earth 
has  since  been  washed  down  during  heavy 
rain,  or  blown  down  during  storms,  from  the 
adjoining  laud  ;  and  this  would  be  especially 
apt  to  occur  where  the  land  has  long  been 
cultivated.  In  the  above  cases  the  adjoining 
land  is  some^vhat  higher  than  the  three  speci- 
fied sites,  as  far  as  I  can  judge  by  maps  and 
from  information  given  me  by  Dr.  Johnson. 
If,  however,  a  great  pile  of  broken  stones 
mortar,  plaster,  timber  and  ashes  fell  over  the 
remains  of  any  building,  their  disintegration 
in  the  course  of  time,  and  the  sifting  action 
of  wormSj  would  ultimately  conceal  the  whole 
beneath  fine  earth. 

Conclusion. — The  cases  given  in  this  chapter 
show  that  worms  have  played  a  considerable 
part  in  the  burial  and  concealment  of  several 
Roman  and  other  old  buildings  in  England  ; 
but  no  doubt  the  washing  down  of  soil  from 
the  neighbouring  higher  lands,  and  the  de- 
position of  dust,  have  together  aided  largely 
in  the  work  of  concealment.  Dust  would  be 
apt  to  accumulate  wherever  old  broken-down 
walls  projected  a  little  above  the  then  exist- 


Chap.  IV.         OF   ANCIENT   BUILDINGS.  229 

ing  surface  and  thus  afforded  some  shelter. 
The  floors  of  the  old  rooms,  halls  and  passages 
have  generally  sunk,  partly  from  the  settling 
of  the  ground,  but  chiefly  from  having  been 
undermined  by  worms;  and  the  sinking  has 
commonly  been  greater  in  the  middle  than 
near  the  walls.  The  walls  themselves,  when- 
ever their  foundations  do  not  lie  at  a  great 
depth,  have  been  penetrated  and  undermined 
by  worms,  and  have  consequently  subsided. 
The  unequal  subsidence  thus  caused,  probably 
explains  the  great  cracks  which  may  be  seen 
in  many  ancient  walls,  as  well  as  their 
inclination  from  the  perpendicular. 


liJO  DISINTEGRATION  Chap.  V. 


CHAPTER  Y. 

THE  ACTION  OF  WORMS  IN^  THE  DExVUDATION 
OF  THE  LAND. 

Evidence  of  the  amount  of  denudation  which  the  land  has 
undergone — Subaerial  denudation — The  depo^ition  of  dust — 
Vegetable  mould,  its  dark  colour  and  fine  texture  largely  due 
to  the  action  of  worms — The  disintegration  of  rocks  by  the 
humus-acids — Similar  acids  apparently  generated  within  the 
bodies  of  worms — The  action  of  these  acids  facilitated  by  the 
continued  movement  of  the  particles  of  earth — A  thick  bed  of 
mould  checks  the  disintegration  of  the  underlying  soil  and 
rocks.  Particles  of  stone  worn  or  triturated  in  the  gizzards  ot 
worms — Swallowed  stones  serve  as  mill-stones— The  levi- 
gated state  of  the  castings — Fragments  of  brick  in  the  castings 
over  ancient  buildings  well  rounded.  The  triturating  power  of 
worms  not  quite  insignificant  under  a  geological  point  of  view. 

No  one  doubts  that  our  world  at  one  time 
consisted  of  crystalline  rocks,  and  that  it  is  to 
their  disintegration  through  the  action  of  air, 
water,  changes  of  temperature,  rivers,  waves 
of  the  sea,  earthquakes  and  volcanic  outbursts, 
that  we  owe  our  sedimentary  formations. 
These  after  being  consolidated  and  sometimes 


Chap.  Y.  AND   DENUDATION.  231 

recrystalllzed,  have  often  been  again  dis- 
integrated. Denudation  means  the  removal 
of  such  disinteo^rated  matter  to  a  lower  level. 
Of  the  many  striking  results  due  to  the 
modern  progress  of  geology  there  are  hardly 
any  more  striking  than  those  which  relate  to 
denudation.  It  was  long  ago  seen  that 
there  must  have  been  an  immense  amount 
of  denudation  ;  but  until  the  successive  forma- 
tions were  carefully  mapped  and  measured, 
no  one  fully  realised  how  great  was  the 
amount.  One  of  the  first  and  most  remark- 
able memoirs  ever  published  on  this  subject 
was  that  by  Ramsay,*  who  in  1846  showed 
that  in  Wales  from  9000  to  11,000  feet  in 
thickness  o''  solid  rock  had  been  stripped  of! 
large  tracks  of  country.  Perhaps  the  plainest 
evidence  of  great  denudation  is  afforded  by 
faults  or. cracks,  which  extend  for  many  miles 
across  certain  districts,  with  the  strata  on  one 
side  raised  even  ten  thousand  feet  above  the 
corresponding  strata  on  the  opposite  side  ;  and 
yet  there  is  not  a  vestige  of  this  gigantic 
displacement   visible   on    the    surface   of  the 

*  "  On  the  denudation  of  South  Wales,"  &c.,  '  Memoirs  of  tha 
Geological  Survey  of  Great  Britain,'  vol.  i.,  p.  297,  1846. 
1(} 


2o2  DISINTEGEATION  Cuap.  V 

land.     A  huge  pile  of  rock  has  been  planed 
away  on  one  side  and  not  a  remnant  left. 

Until  the  last  twenty  or  thirty  years,  most 
geologists  thought  that  the  waves  of  the  sea 
were  the  chief  agents  in  the  work  of  denuda- 
tion ;  but  we  may  now  feel  sure  that  air  and 
rain,  aided  by  streams  and  rivers,  are  much 
more  powerful  agents, — that  is  if  we  consider 
the  whole  area  of  the  land.  The  long  lines  of 
escarpment  which  stretch  across  several  parts 
of  England  were  formerly  considered  to  be 
undoubtedly  ancient  coast-lines ;  but  we  now 
know  that  they  stand  u|)  above  the  general 
surface  merely  from  resisting  air,  rain  and 
frost  better  than  the  adjoining  formations. 
It  has  rarely  been  the  good  fortune  of  a 
geologist  to  bring  conviction  to  the  minds  of 
his  fellow-workers  on  a  disputed  point  by  a 
single  memoir;  but  Mr.  Whitaker,  of  the 
Geological  Survey  of  England,  was  so  for- 
tunate when,  in  1867,  he  published  his  paper 
''  On  sub-aerial  Denudation,  and  on  Cliffs  and 
Escarpments    of  the    Chalk."  *     Before   thi.s 

*  '  Geological  Magazine,'  October  and  November,  1867,  vol. 
Iv.  pp.  447  and  483.  Copious  references  on  the  subject  are  giv,.a 
in  tiiis  remarkal)le  memoir. 


Chap.  V.  AND   DENUDATION.  233 

paper  appeared,  Mr.  A.  Tylor  had  adduced 
important  evidence  on  sub-aerial  denudation, 
by  showing  that  the  amount  of  matter 
brought  down  by  rivers  must  infaUibly  low^er 
the  level  of  their  drainage-basins  by  many 
feet  in  no  immense  lapse  of  time.  This  line 
of  argument  has  since  been  foUov^^ed  up  in  the 
most  interesting  manner  by  Archibald  Geikie, 
Croll  and  others,  in  a  series  of  valuable 
memoirs.*  For  the  sake  of  those  who  have 
never  attended  to  this  subject,  a  single 
instance  may  be  here  given,  namely  that  of 
the  Mississippi,  which  is  chosen  because  the 
amount  of  sediment  brought  down  by  this 
great  river  has  been  investigated  with  especial 
care  by  order  of  the  United  States  Govern- 
ment. The  result  is,  as  Mr.  Croll  shows,  that 
the    mean    level    of    its    enormous    area    of 

*  A.  Tylor  "  On  changes  of  the  sea-level,"  &c.,  '  Philosophical 
Mag.'  (Ser.  4th)  vol.  v.,  1853,  p.  258.  Archibald  Geikie, 
Transactions  Greolog.  Soc.  of  Glasgow,  vol.  iii.,  p.  153  (read  March, 
1868).  Croll  "On  Geologicaf  Time,"  'Philosophical  Mag.', 
May,  August,  and  November,  18G8.  See  also  Croll,  '  Climate 
and  Time,'  1875,  Chap.  XX.  For  some  recent  information  on 
ihe  amount  of  sediment  brought  down  by  rivers,  see  *  Nature,' 
Sept.  23rd,  1880.  Mr.  T.  Mellard  Peade  has  published  some 
interesting  articles  on  the  astonishing  amount  of  matter 
brought  down  in  solution  by  rivers.  See  Address,  Gcolog.  Soc., 
Liverpool,  187G-77. 


234  DISINTEGRATION  Chap.  V 

drainage  must  be  lowered  ^sVe  ^^  ^  ^^'^^ 
annaally,  or  1  foot  in  4566  years.  Con- 
sequently, taking  the  best  estimate  of  the 
mean  height  of  the  North  American  continent, 
viz.  748  feet,  and  looking  to  the  future,  the 
whole  of  the  great  Mississippi  basin  will  be 
washed  away,  and  ''  brought  down  to  the  sea- 
^' level  in  less  than  4,500,000  years,  if  no 
"  elevation  of  the  land  takes  place."  Some 
rivers  carry  down  much  more  sediment  re- 
latively to  their  size,  and  some  much  less  than 
the  Mississippi. 

Disintegrated  matter  is  carried  away  by 
the  wind  as  well  as  by  running  water 
During  volcanic  outbursts  much  rock  is 
triturated  and  is  thus  widely  dispersed ;  and 
in  all  arid  countries  the  wind  plays  an  im- 
portant part  in  the  removal  of  such  matter. 
Wind-driven  sand  also  wears  down  the 
hardest  rocks.  I  have  shown  *  that  during 
four  months  of  the  year  a  large  quantity  of 
dust  is  blown  from  the  north-western  shores 
of  Africa,  and  falls  on  the  Atlantic  over  a 


*  '*  An  account  of  the  fine  dust  which  often  fcills  on  Vessels  in 
the  Atlantic  Ocean,"  Proc.  Gee  log.  Soc.  of  London,  Jime  4ih, 

lb45. 


Chap.  V.  AND   DENUDATION.  235 

space  of  1600  miles  in  latitude,  and  for  a 
distance  of  from  300  to  600  miles  from  the 
coast.  But  dust  has  been  seen  to  fall  at  a 
distance  of  1030  miles  from  the  shores  of 
Africa.  During  a  stay  of  three  weeks  at 
St.  Jago  in  the  Cape  Verde  Archipelago,  the 
atmosphere  was  almost  always  hazy,  and  ex- 
tremely fine  dust  coming  from  Africa  was  con- 
tinually falling.  In  some  of  this  dust  which 
fell  in  the  open  ocean  at  a  distance  of  between 
330  and  380  miles  from  the  African  coast,  there 
were  many  particles  of  stone,  about  y^Q-o  of  an 
inch  square.  Nearer  to  the  coast  the  water 
has  been  seen  to  be  so  much  discoloured  by 
the  falling  dust,  that  a  sailing  vessel  left  a 
track  behind  her.  In  countries,  like  the  Cape 
Yerde  Archipelago,  where  it  seldom  rains 
and  there  are  no  frosts,  the  solid  rock  never- 
theless disintegrates  ;  and  in  conformity  with 
the  views  lately  advanced  by  a  distinguished 
Belgian  geologist,  De  Koninck,  such  disin- 
tegration may  be  attributed  in  chief  part  to 
the  action  of  the  carbonic  and  nitric  acids, 
together  with  the  nitrates  and  nitrites  of 
ammonia,  dissolved  in  the  dew. 

In    all    humid,    even    moderately    humid, 


23G  DISINTEGEATION  Chap.  V. 

countries,  worms  aid  in  the  work  of  denuda- 
tion in  several  ways.  The  vegetable  mould 
which  covers,  as  with  a  mantle,  the  surface 
of  the  Land,  has  all  passed  many  times 
through  their  bodies.  Mould  differs  in  ap- 
pearance from  the  subsoil  only  in  its  dark 
colour,  and  in  the  absence  of  fragments  or 
particles  of  stone  (when  such  are  present  in 
the  subsoil),  larger  than  those  which  can  pass 
through  the  alimentary  canal  of  a  worm. 
This  sifting  of  the  soil  is  aided,  as  has  already 
been  remarked,  by  burrowing  animals  of 
many  kinds,  especially  by  ants.  In  countries 
wdiere  the  summer  is  long  and  dry,  the 
mould  in  protected  places  uiust  be  largely 
increased  by  dust  blown  from  other  and  more 
exposed  places.  For  instance,  the  quantity 
of  dust  sometimes  blown  over  the  plains  of 
La  Plata,  where  there  are  no  solid  rocks,  is 
so  great,  that  during  the  "  gran  seco,"  1827 
to  1830,  the  appearance  of  the  land,  which 
is  here  unenclosed,  was  so  completely  changed 
that  the  inhabitants  could  not  recognise  the 
limits  of  their  own  estates,  and  endless  law- 
suits arose.  Immense  quantities  of  dust  are 
likewise  blov/n  about  in  Egypt  and    in   the 


Chap.  Y.  AND   DENUDATION.  237 

south  of  France.  In  China,  as  Richthofen 
maintains,  beds  appearing  like  fine  sediment, 
several  hundred  feet  in  thickness  and  extend- 
ing over  an  enormous  area,  owe  their  origin 
to  dust  blown  from  the  high  lands  of  central 
Asia.*  In  humid  countries  like  Great 
Britain,  as  long  as  the  land  remains  in  its 
natural  state  clothed  with  vegetation,  the 
mould  in  any  one  place  can  hardly  be  much 
increased  by  dust ;  but  in  its  present  con- 
dition^ the  fields  near  high  roads,  where  there 
is  much  traffic,  must  receive  a  considerable 
amount  of  dust,  and  when  fields  are  harrowed 
during  dry  and  windy  weather,  clouds  of  dust 
may  be  seen  to  be  blown  away.  But  in  all 
these  cases  the  surface-soil  is  merely  trans- 
ported from  one  place  to  another.  The  dust 
which  falls  so  thickly  within  our  houses  con- 


*  For  La  Plata,  see  my  *  Journal  of  Eesearches,'  during  the 
TDyage  of  the  Beagle,  1845,  p.  133.  !^lie  de  Beaumont  has 
given  ('  Le9ons  de  Geolog.  pratique,'  torn.  I,  1845,  p.  183)  an 
excellent  account  of  the  enormous  quantity  of  dust  which  is 
transported  in  some  countries.  I  cannot  but  think  that  Mr. 
Proctor  has  somewhat  exaggerated  ('  Pleasant  Ways  in  Science,' 
1879,  p.  379)  the  agency  of  dust  in  a  humid  country  like  Great 
Britain.  James  Geikie  has  given  ('  Prehistoric  Europe,'  1880, 
p.  165)  a  full  abstract  of  Richthofen's  views,  which,  however, 
he  disputes. 


238  DISINTEGRATION  Chap.  Y 

sists  largely  of  organic  matter,  and  if  spread 
over  the  land  would  in  time  decay  and  dis- 
appear almost  entirely.  It  appears,  however, 
from  recent  observations  on  the  snow-fields 
of  the  Arctic  rea-ions,  that  some  Httle  meteoric 
dust  of  extra  mundane  origin  is  continually 
falling. 

The  dark  colour  of  ordinary  mould  is 
obviously  due  to  the  presence  of  decaying 
organic  matter,  which,  however,  is  present  in 
but  small  quantities.  The  loss  of  weight 
which  mould  suffers  when  heated  to  redness 
seems  to  be  in  large  part  due  to  water  in  com- 
bination being  dispelled.  In  one  sample  of 
fertile  mould  the  amount  of  organic  matter 
was  ascertained  to  be  only  1-76  per  cent. ;  in 
some  artificially  prepared  soil  it  was  as  much 
as  5*5  per  cent.,  and  in  the  famous  black  soil  ol 
Eussia  from  5  to  even  12  per  cent.*  In  leaf- 
mould  formed  exclusively  by  the  decay  of 
leaves  the  amount  is  much  greater,  and  in 
peat  the  carbon  alone  sometimes  amounts  to 


*  These  statements  are  taken  from  Von  Hensen  in  *  Zeitsclirift 
fiir  wissenschaft.  Zoologie,'  Bd.  xxviii.,  1877,  p.  360.  Those 
with  respect  to  peat  are  taken  from  Mr.  A.  A.  Julien  in  *  Proc 
American  Assoc.  Science,  1879,  p.  314. 


Chap.  Y.  AND  DENUDATION.  239 

64  per  cent. ;  but  with  tliese  latter  cases  we 
are  not  here  concerned.  The  carbon  in  the 
soil  tends  gradually  to  oxidise  and  to  dis- 
appear, except  where  water  accumulates  and 
the  climate  is  cool  ;  *  so  that  in  tlie  oldest 
pasture-land  there  is  no  great  excess  of 
organic  matter,  notwithstanding  the  con- 
tinued decay  of  the  roots  and  the  underground 
stems  of  plants,  and  the  occasional  addition 
of  manure.  The  disappearance  of  the  organic 
matter  from  mould  is  probably  much  aided 
by  its  being  brought  again  and  again  to  the 
surface  in  the  castings  of  worms. 

Worms,  on  the  other  hand,  add  largely  to 
the  organic  matter  in  the  soil  by  the  astonish- 
ing number  of  half-decayed  leaves  which 
they  draw  into  their  burrows  to  a  depth  of  2 
or  3  inches.  They  do  this  chiefly  for  obtain- 
ing food,  but  partly  for  closing  the  mouths 
of  their  burrows  and  for  lining  the  upper 
part.  The  leaves  which  they  consume  are 
moistened,  torn  into  small  shreds,  partially 
digested^    and    intimately    commingled    with 

*  I  have  given  some  facts  on  the  climate  necessary  or  favour- 
able for  the  formation  of  peat,  in  my  '  Journal  of  Researches, 
1845,  p.  287. 


240  DISINTEGKATION  Chap.  Y. 

earth  ;  and  it  is  this  process  ^hich  gives  to 
vegetable  mould  its  uniform  dark  tint.  It  is 
known  that  various  kinds  of  acids  are  gen- 
erated by  the  decay  of  vegetable  matter  ;  and 
fiom  the  contents  of  the  intestines  of  worms  and 
from  their  castings  being  acid,  it  seems  pro- 
bable that  the  process  of  digestion  induces  an 
analogous  chemical  change  in  the  swallowed, 
triturated,  and  half  decayed  leaves.  The  large 
quantity  of  carbonate  of  lime  secreted  by  the 
calciferous  glands  apparently  serves  to  neutra- 
lise the  acids  thus  generated ;'  for  the  digestive 
fluid  of  worms  will  not  act  unless  it  be  alkaline. 
As  the  contents  of  the  upper  part  of  their  in- 
testines are  acid,  the  acidity  can  hardly  be  due 
to  the  presence  of  uric  acid.*  We  may  there- 
fore conclude  that  the  acids  in  the  alimentary 
canal  of  w^orms  are  formed  during  the  diges- 
tive process ;  and  that  probably  they  are 
nearly  of  the  same  nature  as  those  in  ordinary 
humus.  The  latter  are  Avell  known  to  have 
the  power  of  de-oxidising  or  dissolving  per- 
oxide of  iron,  as  may  be  seen  wherever  peat 
overlies  red  sand,  or  where  a  rotten  root 
penetrates  such  sand.  Now  I  kept  some 
woims  in  a  pot  filled  with  very  fine  reddish 


Chap.  V.  AND   DEN  UDATION.         .  241 

sand,  consisting  of  minute  particles  of  silex 
coated  with  the  red  oxide  of  iron  ;  and  the 
burrows,  which  the  worms  made  through  this 
sand,  were  lined  or  coated  in  the  usual  manner 
with  their  castings,  formed  of  the  sand  mingled 
with  their  intestinal  secretions  and  the  refuse 
of  the  digested  leaves;  and  this  sand  had 
almost  wholly  lost  its  red  colour.  When 
small  portions  of  it  were  placed  under  the 
microscope,  most  of  the  grains  were  seen  to 
be  transparent  and  colourless,  owing  to  the 
dissolution  of  the  oxide;  whilst  almost  all  the 
grains  taken  from  other  parts  of  the  pot  were 
coated  with  the  oxide.  Acetic  acid  produced 
hardly  any  effect  on  this  sand ;  and  even 
hydrochloric,  nitric  and  sulphuric  acids, 
diluted  as  in  the  Pharmacopoeia^  produced 
less  effect  than  did  the  acids  in  the  intestines 
of  the  worms. 

Mr.  A.  A.  Julien  has  lately  collected  all 
the  extant  information  about  the  acids  gen- 
erated in  humus,  which,  according  to  some 
chemists,  amount  to  more  than  a  dozen 
different  kinds.  These  acids,  as  well  as  their 
acid  salts  (i.e.,  in  combination  with  potash, 
Boda,    and    ammonia),    act    energetically    on 


212  DISINTEGRATION  Chap.  V, 

carbonate  of  lime  and  on  the  oxides  of  iron. 
It  is,  also,  known  that  some  of  these  acids, 
which  were  called  lons^  ago  by  Thenard  azo- 
humic,  are  enabled  to  dissolve  colloid  silica  in 
proportion  to  the  nitrogen  which  they  contain.* 
In  the  formation  of  these  latter  acids  worms 
probably  afford  some  aid,  for  Dr.  H.  Johnson 
informs  me  that  by  Nessler's  test  he  found 
0*018  per  cent,  of  ammonia  in  their  castings. 
The  several  humus-acids,  which  appear,  as 
we  have  just  seen,  to  be  generated  within  the 
bodies  of  worms  during  the  digestive  process, 
and  their  acid  salts,  play  a  highly  important 
part,  according  to  the  recent  observations  of 
Mr.  Julien,  in  the  disintegration  of  various 
kinds  of  rocks.  It  has  long  been  known  that 
the  carbonic  acid,  and  no  doubt  nitric  and 
nitrous  acids,  which  are  present  in  rain-water, 
act  in  like  manner.  There  is,  also,  a  great 
excess  of  carbonic  acid  in  all  soils,  especially 
in  rich  soils,  and  this  is  dissolved  by  the  water 

*  A.  A.  Julieu  "  On  the  Geological  action  of  the  Humus-acids," 
'  Proc.  American  Assoc.  Science,'  vol.  xxviii.,  1879,  p.  311. 
Aho  on  "  Chemical  erosion  on  Mountain  Summits ;"  ' New  York 
Academy  of  Sciences,'  Oct.  14,  1878,  as  quoted  in  the  'American 
Katuralist.'  See  also,  on  this  subject,  S.  W.  Johnson,  '*  How 
Crops  Feed,"  1870,  p.  138 


Chap.  V.  AND   DENUDATION,  243 

in  the  ground.  The  living  roots  of  plantS; 
moreover,  as  Saclis  and  others  have  shown, 
quickly  corrode  and  leave  their  impressions 
on  polished  slabs  of  marble,  dolomite  and 
phosphate  of  lime.  They  will  attack  even 
basalt  and  sandstone.*  But  we  are  not  hero 
concerned  with  agencies  which  are  wholly 
independent  of  the  action  of  worms. 

The  combination  of  any  acid  with  a  base 
is  much  facilitated  by  agitation,  as  fresh 
surfaces  are  thus  continually  brought  into 
contact.  This  will  be  thoroughly  effected 
with  the  particles  of  stone  and  earth  in  the 
intestines  of  worms,  during  the  digestive  pi'o- 
cess  ;  and  it  should  be  remembered  that  tho 
entire  mass  of  the  mould  over  every  field, 
passes,  in  the  course  of  a  few  years,  through 
their  alimentary  canals.  Moreover  as  the  old 
burrows  slowly  collapse,  and  as  fresh  castings 
are  continually  brought  to  the  surface,  the 
whole  superficial  layer  of  mould  slowly  re- 
volves  or  circulates ;  and  the  friction  of  the 
particles  one  with  another  will  rub  off  the 
finest  films  of  disintegrated  matter  as  soon  aa 

*  See,  for  references  on  this  subject,  S.  W.  Johnson,  "  How 
Crops  Feed,"  1870,  p.  326. 


244  DISINTEGRATION  Chap.  V. 

they  are  formed.  Througli  these  several 
means,  minute  fragments  of  rocks  of  many 
kinds  and  mere  particles  in  the  soil  will  be 
continually  exposed  to  chemical  decomposi- 
tion ;  and  thus  the  amount  of  soil  will  tend 
to  increase. 

As  worms  line  their  burrows  with  their 
castings,  and  as  the  burrows  penetrate  to  a 
depth  of  5  or  6,  or  even  more  feet,  some 
small  amount  of  the  humus-acids  will  be 
carried  far  down,  and  will  there  act  on  the 
underlying  rocks  and  fragments  of  rock. 
Thus  the  thickness  of  the  soil,  if  none  be  re- 
moved from  the  surface,  w^ill  steadily  though 
slowly  tend  to  increase  ;  but  the  accumulation 
will  after  a  time  delay  the  disintegration  of 
the  underlying  rocks  and  of  the  more  deeply 
seated  particles.  For  the  humus-acids  which 
are  generated  chiefly  in  the  upper  layer  of 
vegetable  mould,  are  extremely  unstable  com- 
pounds, and  are  liable  to  decomposition  before 
they  reach  any  considerable  depth.*  A  thick 
bed  of  overlying  soil  will  also  check  the 
downward  extension  of  great  fluctuations  of 
temperature,  and  in  cold  countries  will  check 

•  This  statement  is  taken  from  Mr,  Julien,  '  Pioc.  American 
Assoc.  Science  '  vol.  xxviii.,  1879,  p.  330. 


Chap.  Y.  AND   DENUDATION.  2 15 

tlie  powerful  action  of  frost.  TLe  free  access 
of  air  will  likewise  be  excluded.  From  those 
several  causes  disintegration  would  be  almost 
arrested,  if  the  overlying  mould  were  to 
increase  much  in  thickness,  owing  to  none  or 
little  being  removed  from  the  surface.*  In 
my  own  immediate  neighbourhood  we  have  a 
curious  proof  how  effectually  a  few  feet  of 
clay  checks  some  change  which  goes  on  in 
flints,  lying  freely  exposed ;  for  the  large 
ones  which  have  lain  for  some  time  on  the 
surface  of  ploughed  fields  cannot  be  used  for 
building;  they  will  not  cleave  properly  and 
are  said  by  the  workmen  to  be  rotten,  f     It  is 

*  The  preservative  power  of  a  layer  of  mould  and  turf  is  often 
stcwTi  by  the  perfect  state  of  the  glacial  scratches  on  rocks  when 
first  uncovered.  Mr.  J.  Geikie  maintains,  in  his  last  very  inter- 
esting work  ('  Prehistoric  Europe,'  1881),  that  the  more  perfect 
scratches  are  probably  due  to  the  last  access  of  cold  and  increase 
of  ice,  during  the  long-continued,  intermittent  glacial  period. 

f  Many  geologists  have  felt  much  surprise  at  the  complete 
disappearance  of  flints  over  wide  and  nearly  level  areas,  from 
\vhich  the  chalk  has  been  removed  by  subaerial  denudation. 
But  the  surface  of  every  flint  is  coated  by  an  opaque  modified 
layer,  which  will  just  yield  to  a  steel  point,  whilst  the  freshly- 
fractured,  translucent  surface  will  not  thus  yield.  The  re- 
moval by  atmospheric  agencies  of  the  outer  modified  surfaces 
of  freely  exposed  flints,  though  no  doubt  excessively  slow,  to- 
gether with  the  modification  travelling  inwards,  will,  as  may  Vq 
suspected,  ultimately  lead  to  their  complete  disintegration,  not- 
withstanding  that  they  appear  to  be  so  extremely  durable. 


246  DISINTEGRATION  Chap.  V. 

therefore  necessary  to  obtain  flints  for  build- 
ing purposes  from  the  bed  of  red  clay  over- 
lying the  chalk  (the  residue  of  its  dissolution 
by  rainwater)  or  from  the  chalk  itself. 

Not  only  do  worms  aid  indirectly  in  the 
chemical  disintegration  of  rocks,  but  there  is 
good  reason  to  believe  that  they  likewise  act 
in  a  direct  and  mechanical  manner  on  the 
smaller  particles.  All  the  species  which 
swallow  earth  are  furnished  with  gizzards ; 
and  these  are  lined  with  so  thick  a  chitinous 
membrane,  that  Perrier  speaks  of  it,*  as  ^'  une 
veritable  armature."  The  gizzard  is  sur- 
rounded by  powerful  transverse  muscles, 
which,  according  to  Claparede,  are  about  ten 
times  as  thick  as  the  longitudinal  ones ;  and 
Perrier  saw  them  contracting  energetically. 
Worms  belonging  to  one  genus,  Digaster, 
have  two  distinct  but  quite  similar  gizzards ; 
and  in  another  genus,  Moniligaster,  the 
second  gizzard  consists  of  four  pouches,  one 
succeeding  the  other,  so  that  it  may  almost 
be  said  to  have  five  gizzards.f     In  the  same 

•  '  Archives  de  Zoolog.  exper.'  torn.  iii.  1874,  p.  409. 
t  '  Nouvelles  Archives  du  Museum,'  torn.  viii.  1872,  p.  95| 
131. 


Chap.  V.  AND  DENUDATION.  247 

manner  as  gallinaceous  and  strufchious  birds 
swallow  stones  to  aid  in  the  trituration  of 
their  food,  so  it  appears  to  be  with  terricolous 
worms.  The  gizzards  of  thirty-eight  of  our 
common  worms  were  opened,  and  in  twenty- 
five  of  them  small  stones  or  grains  of  sand, 
sometimes  together  with  the  hard  calcareous 
concretions  formed  within  the  anterior  cal- 
ciferous  glands,  were  found,  and  in  two  others 
concretions  alone.  In  the  gizzards  of  the 
remaining  worms  there  were  no  stones ;  but 
some  of  these  were  not  real  exceptions,  a? 
the  gizzards  were  opened  late  in  the  autumn 
when  the  worms  had  ceased  to  feed  and  theii 
gizzards  were  quite  empty.* 

When  worms  make  their  burrows  through 
earth  abounding  with  little  stones,  no  doubt 
many  will  be  unavoidably  swallowed ;  but 
it  must  not  be  supposed  that  this  fact 
accounts  for  the  frequency  with  which  stones 
and  sand  are  found  in  their  gizzards.  For 
beads  of  glass  and  fragments  of  brick  and  of 
hard   tiles   were   scattered   over  the   surface 

*  Morren,  in  speaking  of  the  earth  in  the  alimentary  canals  oi 
worms,  says,  "  praesepfe  cum  lapillis  commixtam  vidi ; "  *  De 
Lumbrici  terrestris,'  &c.,  1829,  p.  16. 

ir 


248  DISINTEGRATION  Cuap.  V. 

of  the  earth,  in  pots  in  which  worms  were 
kept  and  had  already  made  their  burrows  ; 
and  very  many  of  these  beads  and  fragments 
were  picked  np  and  swallowed  by  the  worms, 
for  they  were  found  in  their  castings,  intes- 
tines, and   gizzards.     They    even    swallowed 
the  coarse  red  dust,  formed  by  the  pounding 
of  the   tiles.     Nor   can  it   be  supposed  thai 
they  mistook    the   beads   and   fragments  for 
food ;  for  we  have   seen  that    their   taste   is 
delicate  enough   to  distinguish   between  dif- 
ferent   kinds    of    leaves.       It    is    therefore 
manifest    that    they    swallow    hard    objects, 
such    as   bits   of   stone,    beads   of   glass   and 
angular    fragments    of    bricks    or    tiles    for 
some  special  purpose  ;    and  it  can  hardly  be 
doubted   that    this   is    to    aid   their    gizzards 
in  crushing  and  grinding   the   earth,  which 
they  so   largely  consume.     That   such   hard 
objects     are     not     necessary     for     crushing 
leaves,    may     be     inferred     from     the     fact 
that    certain    species,    which    live    in    mud 
or    water     and     feed     on     dead     or    living 
vegetable  matter,  but  which  do  not  swallow 
earth,  are  not  provided  with  gizzards,*  and 

•  Perrier,  '  Archives  de  Zoolog.  exper.'  torn.  iii.  1874,  p.  419, 


CiiAr.  V.  AND   DENUDATION.  249 

therefore  cannot  have  the  poAver  of  utilising 
stones. 

During  the  grinding  process,  the  particles 
of  earth  must  he  ruhbed  against  one  another, 
and  between  the  stones  and  the  tough 
lining  membrane  of  the  gizzard.  The  softer 
particles  will  thus  suffer  some  attrition,  and 
will  perhaps  even  be  crushed.  This  con- 
clusion is  supported  by  the  appearance  of 
freshly  ejected  castings,  for  these  often  re- 
minded me  of  the  appearance  of  paint  which 
has  just  been  ground  by  a  workman  between 
two  flat  stones.  Morren  remarks  that  the 
intestinal  canal  is  ''  impleta  tenuissima  terra, 
veluti  in  pulverem  redacta."  *  Perrier  also 
speaks  of  "  I'etat  de  pate  excessivement  fine  a 
laquelle  est  reduite  la  terre  qu'ils  rejettent," 
&c.t 

As  the  amount  of  trituration  which  the 
particles  of  earth  undergo  in  the  gizzards 
of  worms  possesses  some  interest  (as  we 
shall  hereafter  see),  I  endeavoured  to  obtain 
evidence  on  this  head  by  carefully  examining 
many   of  the   fragments   which   had   passed 

*  Morren,  *  De  Lumbrici  terrestris,'  &c.,  p.  1 6. 

X  '  Archives  de  Zoolog.  Expdr.'  torn.  iii.  1874,  p.  418. 


250  DISINTEGKATION  CnAr.  V. 

through  their  alimentary  canals.  With 
worms  living  in  a  state  of  nature,  it  is  of 
CDurse  impossible  to  know  how  much  the 
fragments  may  have  been  worn  before  they 
were  swallowed.  It  is,  however,  clear  that 
worms  do  not  habitually  select  already 
rounded  particles,  for  sharply  angular  bits 
of  flint  and  of  other  hard  rocks  were  often 
found  in  their  gizzards  or  intestines.  On 
three  occasions  sharp  spines  from  the  stems 
of  rose-bushes  were  thus  found.  Worms  kept 
in  confinement  repeatedly  swallowed  angular 
fragments  of  hard  tile,  coal,  cinders,  and  even 
the  sharpest  fragments  of  glass.  Gallinaceous 
and  struthious  birds  retain  the  same  stones 
in  their  gizzards  for  a  long  time,  which  thus 
become  well  rounded ;  but  this  does  not 
appear  to  be  the  case  with  worms,  judging 
from  the  large  number  of  the  fragments  of 
tiles,  glass  beads,  stones,  &c.,  commonly  found 
in  their  castings  and  intestines.  So  that 
unless  the  same  fragments  were  to  pass  re- 
peatedly through  their  gizzards,  visible  signs 
of  attrition  in  the  fragments  could  hardly  be 
expected,  except  perhaps  in  the  case  of  very 
soft  stones. 


Chap.  V.  AND   DENUDATION.  25 1 

I  will  now  give  such  evidence  of  attrition 
as  I  have  been  able  to  collect.  In  the 
gizzards  of  some  worms  dug  out  of  a  thin  bed 
of  mould  over  the  chalk,  there  were  many  well- 
rounded  small  fragments  of  chalk,  and  two 
fragments  of  the  shells  of  a  land-mollusc  (as 
ascertained  by  their  microscopical  structure), 
which  latter  were  not  only  rounded  but 
somewhat  polished.  The  calcareous  concre- 
tions formed  in  the  calciferous  glands,  which 
are  often  found  in  their  gizzards,  intestines, 
and  occasionally  in  their  castings,  when  of 
large  size,  sometimes  appeared  to  have  been 
rounded;  but  with  all  calcareous  bodies 
the  rounded  appearance  may  be  partly  or 
wholly  due  to  their  corrosion  by  carbonic 
acid  and  the  humus-acids.  In  the  gizzards 
of  several  worms  collected  in  my  kitchen 
garden  near  a  hothouse,  eight  little  frag- 
ments of  cinders  were  found,  and  of  these, 
six  appeared  more  or  less  rounded,  as  were 
twc  bits  of  brick;  but  some  other  bits  were 
not  at  all  rounded.  A  farm-road  near 
Abinger  Hall  had  been  covered  seven  years 
before  with  brick-rubbish  to  the  depth  of 
about   6    inches  ;    turf  had  grown   over  this 


252  DISINTEGRx\TION  Chap.  V. 

rubbish  on  both  sides  of  the  road  for  a 
width  of  18  inches,  and  on  this  turf  there 
were  innumerable  castings.  Some  of  them 
were  coloured  of  a  uniform  red  owing  to 
the  presence  of  much  brick-dust,  and  they 
contained  many  particles  of  brick  and  of 
hard  mortar  from  1  to  3  mm.  in  diameter, 
most  of  which  were  plainly  rounded ;  but 
all  these  particles  may  have  been  rounded 
before  they  were  protected  by  the  turf  and 
were  swallowed,  like  those  on  the  bare  parts 
of  the  road  which  were  much  worn.  A  hole 
in  a  pasture-field  had  been  filled  up  with 
brick-rubbish  at  the  same  time^  viz.,  seven 
years  ago,  and  was  now  covered  with  turf; 
and  here  the  castings  contained  very  many 
particles  of  brick,  all  more  or  less  rounded ; 
and  this  brick-rubbish,  after  being  shot  into 
the  hole,  could  not  have  undergone  any 
attrition.  Again,  old  bricks  very  little 
broken,  together  with  fragments  of  mortar, 
w^ere  laid  down  to  form  walks,  and  were 
then  covered  with  from  4  to  6  inches  of 
gravel ;  six  little  fragments  of  brick  were 
extracted  from  castings  collected  on  these 
walks,    three    of  which   were   plainly   worn. 


CiiAP.  Y.  AND   DENUDATION.  253 

There  were  also  very  many  particles  of  hard 
mortar,  about  half  of  which  were  w^ell 
rounded;  and  it  is  not  credible  that  these 
could  have  suffered  so  much  corrosion  from 
the  action  of  carbonic  acid  in  the  course  of 
only  seven  years. 

Much  better  evidence  of  the  attrition  of 
hard  objects  in  the  gizzards  of  worms,  is 
afforded  by  the  state  of  the  small  fragments 
of  tiles  or  bricks,  and  of  concrete  in  the 
castings  thrown  up  where  ancient  buildings 
once  stood.  As  all  the  mould  covering  a 
field  passes  every  few  years  through  the 
bodies  of  worms,  the  same  small  fragments 
will  probably  be  swallowed  and  brought  to 
the  surface  many  times  in  the  course  of  cen- 
turies. It  should  be  premised  that  in  tlie 
several  following  cases,  the  finer  matter  was 
first  washed  away  from  the  castings,  and 
then  all  the  particles  of  bricks,  tiles  and  con- 
crete were  collected  without  any  selection,  and 
were  afterwards  examined.  Now  in  the  cast- 
ings ejected  between  the  tesseras  on  one  of  the 
buried  floors  of  the  Roman  villa  at  Abinger, 
there  were  many  particles  (from  |  to  2  ram. 
in    diameter)  of  tiles  and  concrete,  which  it 


254  DISINTEGKATION  Chap.  Y. 

was  impossible  to  look  at  with  the  naked  eye 
or  through  a  strong  lens,  and  doubt  for  a 
moment  that  they  had  almost  all  undergone 
much  attrition.  I  speak  thus  after  having 
examined  small  water-worn  pebbles,  formed 
from  Roman  bricks,  which  M.  Henri  do 
Saussure  had  the  kindness  to  send  me,  and 
which  he  had  extracted  from  sand  and  gravel 
beds,  deposited  on  the  shores  of  the  Lake  of 
Geneva,  at  a  former  period  when  the  water 
stood  at  about  two  metres  above  its  present 
level.  The  smallest  of  these  water- worn 
pebbles  of  brick  from  Geneva  resembled 
closely  many  of  those  extracted  from  the 
gizzards  of  worms,  but  the  larger  ones  were 
somewhat  smoother. 

Four  castings  found  on  the  recently  un- 
covered, tesselated  floor  of  the  great  room  in 
the  Roman  villa  at  Brading,  contained  many 
particles  of  tile  or  brick,  of  mortar,  and  of 
hard  white  cement ;  and  the  majority  of  these 
appeared  plainly  worn.  The  particles  of 
mortar,  however,  seemed  to  have  suffered 
more  corrosion  than  attrition,  for  grains  of 
si  lex  often  projected  from  their  surfaces. 
Castings  from   within  the  nave  of  Beaulieu 


Chap.  V.  AND  DENUDATION.  255 

Abbey,  which  was  destroyed  by  Henry  YIIl., 
were  collected  from  a  level  expanse  of  turf, 
overlying  the  buried  tesselated  pavement, 
tlirough  which  worm-burrows  passed ;  and 
these  castings  contained  innumerable  particles 
of  tiles  and  bricks,  of  concrete  and  cement, 
the  majority  of  which  had  manifestly  under- 
gone some  or  much  attrition.  There  were 
also  many  minute  flakes  of  a  micaceous  slate, 
the  points  of  which  were  rounded.  If  the  above 
supposition,  that  in  all  these  cases  the  same 
minute  fragments  have  passed  several  times 
through  the  gizzards  of  worms,  be  rejected, 
notwithstanding  its  inherent  probability,  we 
must  then  assume  that  in  all  the  above  cases 
the  many  rounded  fragments  found  in  the 
castings  had  all  accidentally  undergone  much 
attrition  before  they  were  swallowed  ;  and 
this  is  highly  improbable. 

On  the  other  hand  it  must  be  stated  that 
fragments  of  ornamental  tiles,  somewhat 
harder  than  common  tiles  or  bricks,  which 
had  been  swallowed  only  once  by  worms  kept 
in  confinement,  were  with  the  doubtful  ex- 
ception of  one  or  two  of  the  smallest  grains, 
not   at   all    rounded.     Nevertheless  some   of 


2dQ  disintegration  Chap.  V. 

them  appeared  a  little  worn,  though  not 
rounded.  Notwithstanding  these  cases,  if  we 
consider  the  evidence  above  given,  there  can 
be  little  doubt  that  the  fragments,  which  serve 
as  millstones  in  the  gizzards  of  worms,  suffer, 
when  of  a  not  very  hard  texture,  some  amount 
of  attrition ;  and  that  the  smaller  particles  in 
the  earth,  which  is  habitually  swallowed  in 
such  astonishingly  large  quantities  by  worms, 
are  ground  together  and  are  thus  levigated. 
If  this  be  the  case,  the  ^'  terra  tenuissima,"  — 
the  "pate  excessivement  fine," — of  which  the 
castings  largely  consist,  is  in  part  due  to  the 
mechanical  action  of  the  gizzard ;  *  and  this 
fine  matter,  as  we  shall  see  in  the  next  chapter, 
is  that  which  is  chiefly  washed  away  from  the 
innumerable  castings  on  every  field  during 
each  heavy  shower  of  rain.  If  the  softer  stones 
yield  at  all,  the  harder  ones  will  suffer 
some  slight  amount  of  wear  and  tear. 

*  This  conclusion  reminds  me  of  the  vast  amount  of  extremely 
fino  chalky  mud  which  is  found  within  the  lagoons  of  many 
atolls,  where  the  sea  is  tranquil  and  waves  cannot  triturate  the 
blocks  of  coral.  This  mud  must,  as  I  believe  ('  The  Structure  and 
Distribution  of  Coral-Eeefs,' 2nd  edit.  1874,  p.  19),  be  attributed 
to  the  innumerable  annelids  and  other  animals  which  burrow 
into  the  dead  coral,  and  to  the  fishes,  Holothurians,  &c.,  which 
browse  on  th(!  living  corals. 


Chap.  Y.  AND  DENUDATION.  257 

The  trituration  of  small  particles  of  stone 
in  the  gizzards  of  worms  is  of  more  import- 
ance under  a  geological  point  of  view  than 
may  at  first  appear  to  be  the  case  ;  for  Mr. 
Sorby  has  clearly  shown  that  the  ordinary 
means  of  disintegration,  namely  running 
water  and  the  weaves  of  the  sea,  act  with 
less  and  less  power  on  fragments  of  rock  the 
smaller  they  are.  "  Hence,"  as  he  remarks, 
*'  even  making  no  allowance  foi"  the  extra 
"  buoying  up  of  very  minute  particles  by  a 
"  current  of  water,  depending  on  surface 
''  cohesion,  the  effects  of  wearing  on  the  form 
''  of  the  grains  must  vary  directly  as  their 
*'  diameter  or  thereabouts.  If  so,  a  grain  ^^ 
''of  an  inch  in  diameter  would  be  worn  ten 
"  times  as  much  as  one  ^^  of  an  inch  in 
"  diameter,  and  at  least  a  hundred  times  as 
*'  much  as  one  xoVo  ^^  ^^  ^^^^  ^'^  diameter. 
"  Perhaps,  then,  we  may  conclude  that  a 
"  grain  -f^  of  an  inch  in  diameter  would  be 
'^  worn  as  much  or  more  in  drifting  a  mile  as 
*'  a  grain  y^Vo  ^^'  ^'^  ^^^^^^  ^'^  being  drifted 
**  1 00  miles.  On  the  same  principle  a  pebble 
*'  one  inch  in  diameter  would  be  worn  re- 
"  latively  more  hj  being  drifted  only  a  few 


258  DISINTEGRATION,   ETC.  Chap.  V. 

**  hundred  yards."*  Nor  should  we  forget,  in 
considering  the  power  which  worms  exert  in 
triturating  particles  of  rock,  that  there  is  good 
evidence  that  on  each  acre  of  land,  which  is 
sufficiently  damp  and  not  too  sandy,  gravelly 
or  rocky  for  worms  to  inhahit,  a  weight  of 
more  than  ten  tons  of  earth  annually  passes 
through  their  bodies  and  is  brought  to  the 
surface.  The  result  for  a  country  of  the  size 
of  Great  Britain,  within  a  period  not  very 
long  in  a  geological  sense,  such  as  a  million 
years,  cannot  be  insignificant ;  for  the  ten  tons 
of  earth  has  to  be  multiplied  first  by  the  above 
number  of  years,  and  then  by  the  number  ot 
acres  fully  stocked  with  worms ;  and  in 
England,  together  with  Scotland,  the  land 
which  is  cultivated  and  is  v/ell  fitted  for  these 
animals,  has  been  estimated  at  above  32 
million  acres.  The  product  is  320  million 
million  tons  of  earth. 

*  Anniversary    Address :    '  The  Quarterly  Journal    of    the 
Geological  Soc'  May  1880,  p.  50. 


CHAPTER  YI. 

THE  DENUDATION    OF    THE    LAND — Continued, 

Denudation  aided  by  recently  ejected  castings  flowing  down 
inclined  grass-covered  surfaces — The  amount  of  earth  which 
annually  flows  downwards — The  effect  of  tropical  rain  on 
worm  castings — The  finest  particles  of  earth  washed  com- 
pletely away  from  castings — The  disintegration  of  dried  cast- 
ings into  pellets,  and  their  rolling  down  inclined  surfaces — 
The  formation  of  little  ledges  on  hill-sides,  in  part  due  to  the 
accumulation  of  disintegrated  castings — Castings  blown  to 
leeward  over  level  land — An  attempt  to  estimate  the  amount 
thus  blown — The  degradation  of  ancient  encampments  and 
tumuli — The  preservation  of  the  crowns  and  furrows  on  land 
anciently  ploughed — The  formation  and  amount  of  mould 
over  the  Chalk  formation. 

We  are  now  prepared  to  consider  the  more 
direct  part  which  worms  take  in  the  denuda- 
tion of  the  land.  When  reflecting  on  sub- 
aerial  denudation,  it  formerly  appeared  to 
me,  as  it  has  to  others,  that  a  nearly  level  or 
very  gently  inclined  surface,  covered  with 
turf,  could  suffer  no  loss  during  even  a  long 
lapse  of  time.  It  may,  however,  be  urged 
that   at   long  intervals,  debacles  of  rain  or 


260  DE>sUDATION   OF   THE   LAND     Chap.  YI 

water- spouts  would  remove  all  tlie  mould 
from  a  very  gentle  slope  ;  but  when  ex- 
amining the  steep,  turf-covered  slopes  in 
Glen  Roy,  I  was  struck  with  the  fact  how 
rarely  any  such  event  could  have  happened 
since  the  Glacial  period,  as  Avas  plain  from  the 
well-preserved  state  of  the  three  successive 
^'  roads  "  or  lake-margins.  But  the  difficulty 
in  believing  that  earth  in  any  appreciable 
quantity  can  be  removed  from  a  gently  in- 
clined surface,  covered  with  vegetation  and 
matted  with  roots,  is  removed  through  the 
agency  of  worms.  For  the  many  castings 
which  are  thrown  up  during  rain,  and  those 
thrown  up  some  little  time  before  heavy  rain, 
flow  for  a  short  distance  down  an  inclined 
surface.  Moreover  much  of  the  finest  levi- 
gated earth  is  washed  completely  away  from 
the  castings.  During  dry  weather  castings 
often  disintegrate  into  small  rounded  pellets, 
and  these  from  their  weight  often  roll  down 
any  slope.  This  is  more  especially  apt  tv'^ 
occur  when  they  are  started  by  the  wind, 
and  probably  wdien  started  by  the  touch  of  an 
animal,  liowever  small.  "We  shall  also  see 
that   a  strong  wind   blows  all  the  castings, 


Chap.  YI.  AIDED   BY   WOEMS.  261 

even  on  a  level  field,  to  leeward,  whilst  they 
are  soft;  and  in  like  manner  the  pellets 
when  they  are  dry.  If  the  wind  blows  in 
nearly  the  direction  of  an  inclined  surface, 
the  flowing  down  of  the  castings  is  much 
aided. 

The  observations  on  which  these  several 
statements  are  founded  must  now  be  given  in 
some  detail.  Castings  when  first  ejected  are 
viscid  and  soft ;  during  rain,  at  which  time 
worms  apparently  prefer  to  eject  them,  they 
are  still  softer ;  so  that  I  have  sometimes 
thought  that  worms  must  swallow  much 
water  at  such  times.  However  this  may 
Le,  rain,  even  when  not  very  heavy,  if 
long  continued,  renders  recently-ejected 
castings  semi-fluid ;  and  on  level  ground 
they  then  spread  out  into  thin,  circular,  flat 
discs,  exactly  as  would  so  much  honey  or 
very  soft  mortar^  with  all  traces  of  their 
vermiform  structure  lost.  This  latter  fact 
was  sometimes  made  evident,  when  a  worm 
had  subsequently  bored  through  a  flat  circular 
disc  of  this  kind,  and  heaped  up  a  fresh 
vermiform  mass  in  the  centre.  These  flat 
subsided  discs  have  been  repeatedly  seen  hj 


262  DENUDATION   OF   THE  LAND     Chap.  VL 

me  after  heavy  rain,  in  many  places  on  land 
of  all  kinds. 

On  the  flowing  of  wet  castings,  and  the 
rolling  of  dry  disintegrated  eastings  down 
inclined  surfaces,-— Wh^xi  castings  are  ejected 
on  an  inclined  surface  during  or  shortly 
before  heavy  rain,  they  cannot  fail  to  flow  a 
little  down  the  slope.  Thus,  on  some  steep 
slopes  in  Knowle  Park^  which  were  covered 
with  coarse  grass  and  had  apparently  existed 
in  this  state  from  time  immemorial,  I  found 
(Oct.  22,  1872)  after  several  wet  days  that 
almost  all  the  many  castings  were  con- 
siderably elongated  in  the  line  of  the  slope  ; 
and  that  they  now  consisted  of  smooth^  only 
shghtly  conical  masses.  Whenever  the 
mouths  of  the  burrows  could  be  found  from 
which  the  earth  had  been  ejected,  there  was 
more  earth  below  than  above  them.  After 
come  heavy  storms  of  rain  (Jan.  25,  1872) 
two  rather  steeply  inclined  fields  near  Down, 
which  had  formerly  been  ploughed  and  were 
now  rather  sparsely  clothed  with  poor  grass, 
were  visited,  and  many  castings  extended 
down  the  slopes  for  a  length  of  5  inches, 
which  was  twice  or  thrice  the  usual  diameter 


Chap.  VI.  AIDED  BY  WORMS.  263 

of  the  castings  thrown  up  on  the  level  parts 
of  these  same  fields.  On  some  fine  grassy 
slopes  in  Holwood  Park,  inclined  at  angles 
oetween  8"^  and  1 1"^  30'  with  the  horizon, 
where  the  surface  apparently  had  never  been 
disturbed  by  the  hand  of  man,  castings 
abounded  in  extraordinary  numbers ;  and  a 
space  16  inches  in  length  transversely  to  the 
slope  and  6  inches  in  the  line  of  the  slope, 
was  completely  coated,  between  the  blades  of 
grass,  with  a  uniform  sheet  of  confluent  and 
subsided  castings.  Here  also  in  many  places 
the  castings  had  flowed  down  the  slope,  and 
now  formed  smooth  narrow  patches  of  earth, 
6,  7,  and  7^  inches  in  length.  Some  of  these 
consisted  of  two  castings,  one  above  the  other, 
which  had  become  so  completely  confluent 
that  they  could  hardly  be  distinguished.  On 
my  lawn,  clothed  with  very  fine  grass,  most 
of  the  castings  are  black,  but  some  are 
yellowish  from  earth  having  been  brought 
up  from  a  greater  depth  than  usual,  and  the 
fowing-down  of  these  yellow  castings  after 
heavy  rain,  could  be  clearly  seen  where  the 
slope  was  5° ;  and  where  it  was  less  than  1*^ 
gome  evidence  of  their  flowing  down  could 

18 


264  DENUDATION   OF   THE   LAND     Chap.  YL 

still  be  detected.  On  another  occasion,  after 
rain  which  was  never  heavy,  but  which  lasted 
for  18  hours,  all  the  castings  on  this  samo 
gentl};^  inclined  lawn  had  lost  their  vermiform 
structure ;  and  they  had  flowed,  so  that  fully 
two-thirds  of  the  ejected  earth  lay  below  the 
mouths  of  the  burrows. 

These  observations  led  me  to  make  others 
with  more  care.  Eight  castings  were  found  on 
my  lawn,  where  the  grass-blades  are  fine  and 
close  together,  and  three  others  on  a  field  with 
coarse  grass.  The  inclination  of  the  surface  at 
the  eleven  places  where  these  castings  were 
collected  varied  between  4"^  30' and  17°  30'; 
the  mean  of  the  eleven  inclinations  being 
9°  26'.  The  length  of  tlie  castings  in  the 
direction  of  the  slope  was  first  measured  with 
as  much  accuracy  as  their  irregularities  would 
permit.  It  was  found  possible  to  make  these 
measurements  within  about  ^  of  an  inch,  but 
one  of  the  castings  was  too  irregular  to  admit 
of  measurement.  The  average  length  in  the 
direction  of  the  slope  of  the  remaining  ten 
castings  was  2*03  inches.  The  castings  were 
then  divided  with  a  knife  into  two  parts  along 
a  horizontal  line  passing  through  the  mouth 


Chap.  YL  AIDED   BY   WOEMS.  265 

of  tlie  bnrrow,  wliicli  was  discovered  by  slicing 
oiF  the  turf;  and  all  the  ejected  earth  was 
separately  collected,  namely  the  part  above 
the  hole  and  the  part  below.  Afterwards 
these  two  parts  were  weighed.  In  every 
case  there  was  much  more  earth  below  than 
above ;  the  mean  weight  of  that  above  being 
103  grains,  and  of  that  below  205  grains  ;  so 
that  the  latter  was  very  nearly  double  the 
former.  As  on  level  ground  castings  are 
commonly  thrown  np  almost  equally  round 
the  mouths  of  the  burrows,  this  difference  in 
weight  indicates  the  amount  of  ejected  earth 
which  had  flowed  down  the  slope.  But  very 
many  more  observations  would  be  requisite 
to  arrive  at  any  general  result ;  for  the 
nature  of  the  vegetation  and  other  accidental 
circumstances,  such  as  the  heaviness  of  the 
rain,  the  direction  and  force  of  the  wind,  &c., 
appear  to  be  more  important  in  determining 
the  quantity  of  the  earth  which  flows  down  a 
slope  than  its  angle.  Thus  with  four  castings 
on  my  lawn  (included  in  the  above  eleven) 
where  the  mean  slope  was  7°  19',  the  difference 
in  the  amount  of  earth  above  and  below  the 
burrows  was   greater  than  with  three   other 


266  DENUDATION   OF   THE   LAND     Chap.  VL 

castings  on  the  same  lawn  where  the  mean 
slope  was  12°  5'. 

We  may,  however,  take  the  above  eleven 
eases,  which  are  accurate  as  far  as  they  go, 
and  calculate  the  weight  of  the  ejected  earth 
which  annually  flows  down  a  slope  having  a 
mean  inclination  of  9°  26'.  This  was  done 
hy  my  son  George.  It  has  been  shown 
that  almost  exactly  two-thirds  of  the  ejected 
earth  is  found  below  the  mouth  of  the 
burrow  and  one-third  above  it.  Now  if  the 
two-thirds  which  is  below  the  hole  be  divided 
into  two  equal  parts,  the  upper  half  of  this 
two-thirds  exactly  counterbalances  the  one- 
third  which  is  above  the  hole,  so  that  as  far 
as  regards  the  one-thiid  above  and  the  upper 
half  of  the  two-thirds  below,  there  is  no  flow 
of  earth  down  the  hill-side.  The  earth  con- 
stituting the  lower  half  of  the  two-thirds  is, 
however,  displaced  through  distances  which 
are  different  for  every  part  of  it,  but  which 
may  be  represented  by  the  distance  between 
the  middle  point  of  the  lower  half  of  the 
two-thirds  and  the  hole.  So  that  the  average 
distance  of  displacement  is  a  half  of  the 
whole  length  of  the  worm -casting.     Now  the 


Chap.  VI.  AIDED   BY   WOEMS.  267 

average  length  of  ten  out  of  the  above 
eleven  castings  was  2*03  inches,  and  half  of 
this  we  may  take  as  being  one  inch.  It  may 
therefore  be  concluded  that  one-third  of  the 
whole  earth  brought  to  the  surface  was  in 
these  cases  carried  down  the  slope  through 
one  inch. 

It  was  shown  in  the  third  chapter  that  on 
Leith  Hill  Common,  dry  earth  weighing  at 
least  7*453  lbs.  was  brought  up  by  worms  to 
the  surface  on  a  square  yard  in  the  course  of 
a  year.  If  a  square  yard  be  drawn  on  a 
hill-side  with  two  of  its  sides  horizontal,  then 
it  is  clear  that  only  -^  part  of  the  earth 
brought  up  on  that  square  yard  would  be 
near  enough  to  its  lower  side  to  cross  it, 
supposing  the  displacement  of  the  earth  to 
be  through  one  inch.  But  it  appears  that 
only  -J  of  the  earth  brought  up  can  be  con- 
sidered to  flow  downwards  ;  hence  -g-  of  -g^  or 
-j-^8  of  7*453  lbs.  will  cross  the  lower  side  of 
our  square  yard  in  a  year.  Now  -^ww  ^^ 
7*453  lbs.  is  1*1  oz.  Therefore  1"I  oz.  of  dry 
earth  will  annually  cross  each  linear  yard  run- 
ning horizontally  along  a  slope  having  the 
above  inclination ;  or  very  nearly  7  lbs.  will 


268  DENUDATION   OF   THE   LAND     Chap.  VL 

annually  cross  a  horizontal  line,  100  yards  in 
length,  on  a  hill-side  having  this  iDclination. 

A  more  accurate,  though  still  very  rough, 
calculation  can  be  made  of  the  bulk  of  earth, 
which  in  its  natural  damp  state  annually 
flows  down  the  same  slope  over  a  yard-line 
drawn  horizontally  across  it.  From  the 
several  cases  given  in  the  third  chapter,  it 
is  known  that  the  castings  annually  brought 
to  the  surface  on  a  square  yard,  if  uniformly 
spread  out  would  form  a  layer  *2  of  an  inch 
in  thickness  :  it  therefo]  e  follows  by  a 
calculation  similar  to  the  one  already  given, 
that  -J-  of  '2  X  36^  or  2*4  cubic  inches  of  damp 
earth  will  annually  cross  a  horizontal  line  one 
yard  in  length  on  a  hill-side  with  the  above 
inclination.  This  bulk  of  damp  castings 
was  found  to  weigh  1*85  oz.  Therefore 
11*56  lbs.  of  damp  earth,  instead  of  7  lbs.  of 
dry  earth  as  by  the  former  calculation,  would 
annually  cross  a  line  100  yards  in  Isngth  on 
our  inclined  surface. 

In  these  calculations  it  has  been  assumed 
that  the  castings  flow  a  short  distance  down- 
wards during  the  whole  year,  but  this  occurs 
only  with  those   ejected    during    or   shortly 


CuAP.  VI.  AIDED  BY   WORMS.  269 

before  rain  ;  so  that  the  above  results  are 
thus  far  exaggerated.  On  the  other  hand, 
during  rain  much  of  the  finest  earth  is 
washed  to  a  considerable  distance  from  the 
castings,  even  where  the  slope  is  an  ex- 
tremely gentle  one,  and  is  thus  wholly  lost 
as  far  as  the  above  calculations  are  concerned. 
Castings  ejected  during  dry  weather  and 
which  have  set  hard,  lose  in  the  same 
manner  a  considerable  quantity  of  fine  earth. 
Dried  castings,  moreover,  are  apt  to  disinte- 
grate into  little  pellets,  which  often  roll  or 
are  blown  down  any  inclined  surface.  There- 
fore the  above  result,  namely  that  2*4  cubic 
inches  of  earth  (weighing  1-85  oz.  whilst 
damp)  annually  crosses  a  yard-line  of  the 
specified  kind,  is  probably  not  much  if  at  all 
exaggerated. 

This  amount  is  small ;  but  we  should  bear 
in  mind  how  many  branching  valleys  inter- 
sect most  countries,  the  whole  length  of 
which  must  be  very  great ;  and  that  earth  is 
steadily  travelling  down  both  turf-covered 
sides  of  each  valley.  For  every  100  yards  in 
length  in  a  valley  with  sides  sloping  as  in  the 
foregoing   cases,  480   cubic    inches  of  damp 


270  DENUDATION   OF   THE   LAND     Chap.  YI. 

earth,  weighing  above  23  pounds,  will 
annually  reach  the  bottom.  Here  a  thick 
bed  of  alluvium  will  accumulate,  ready  to  be 
washed  away  in  the  course  of  centuries,  as 
the  stream  in  the  middle  meanders  from  side 
to  side. 

If  it  could  be  shown  that  worms  generally 
excavate  their  burrows  at  right  angles  to 
an  inclined  surface,  and  this  would  be 
their  shortest  course  for  bringing  up  earth 
from  beneath,  then  as  the  old  burrows  col- 
lapsed from  the  weight  of  the  superincum- 
bent soil,  the  collapsing  would  inevitably 
cause  the  whole  bed  of  vegetable  mould  to 
sink  or  slide  slowly  down  the  inclined  sur- 
face. But  to  ascertain  the  direction  of  many 
burrows  was  found  too  difficult  and  trouble- 
some. A  straight  piece  of  wire  was,  how- 
ever, pushed  into  twenty-five  burrows  on 
several  sloping  fields,  and  in  eight  cases  the 
burrows  were  nearly  at  right  angles  to  the 
slope  ;  whilst  in  the  remaining  cases  they  were 
indifferently  directed  at  various  angles,  either 
upwards  or  downwards  with  respect  to  the 
slope. 

In  countries  where  the  rain  is  very  heavy, 


Chap.  VI.  AIDED   BY  WORMS.  271 

as  in  the  tropics,  the  castings  appear,  ag 
might  have  heen  expected,  to  be  washed 
down  in  a  greater  degree  than  in  England. 
Mr.  Scott  informs  me  that  near  Calcutta  the 
tall  columnar  castings  (previously  described), 
the  diameter  of  which  is  usually  between  i 
and  IJ  inch,  subside  on  a  level  surface, 
after  heavy  rain,  into  almost  circular,  thin, 
flat  discs,  between  3  and  4  and  sometimes  5 
inches  in  diameter.  Three  fresh  castings, 
which  had  been  ejected  in  the  Botanic 
Gardens  "  on  a  slightly  inclined,  grass- 
'*  covered,  artificial  bank  of  loamy  clay,"  were 
carefully  measured,  and  had  a  mean  height 
of  2*17,  and  a  mean  diameter  of  1'43  inches  ; 
these  after  heavy  rain,  formed  elongated 
patches  of  earth,  with  a  mean  length  in  the 
direction  of  the  slope  of  5-83  inches.  As  the 
earth  had  spread  very  little  up  the  slope,  a 
large  part,  judging  from  the  original  diameter 
of  these  castings,  must  have  flowed  bodily 
downwards  about  4  inches.  Moreover  some 
of  the  finest  earth  of  which  they  were  com- 
posed must  have  been  washed  completely 
away  to  a  still  greater  distance.  In  drier 
sites  near  Calcutta,  a  species  of  worm  ejects 


272  DENUDATION   OF   THE   LAND     Chap.  VL 

its  castings,  not  in  vermiform  masses,  but  in 
little  pellets  of  varying  sizes  :  these  are  very 
numerous  in  some  places,  and  Mr.  Scott  says 
that  they  "  are  washed  away  by  every 
"  shower." 

I  was  led  to  believe  that  a  considerable 
quantity  of  fine  earth  is  washed  quite  away 
from  castings  during  rain,  from  the  surfaces 
of  old  ones  being  often  studded  with  coarse 
particles.  Accordingly  a  little  fine  precipi- 
tated chalk,  moistened  with  saliva  or  gum- 
water,  so  as  to  be  slightly  viscid  and  of  the 
same  consistence  as  a  fresh  casting,  was 
placed  on  the  summits  of  several  castings  and 
gently  mixed  with  them.  These  castings 
were  then  watered  through  a  very  fine  rose, 
the  drops  from  which  were  closer  together 
than  those  of  rain,  but  not  nearly  so  large  as 
those  in  a  thunder  storm  ;  nor  did  they  strike 
the  ground  with  nearly  so  much  force  as 
drops  during  heavy  rain.  A  casting  ihus 
treated  subsided  with  surprising  slowness, 
owing  as  I  suppose  to  its  viscidity.  It  did 
not  fiow  bodily  down  the  grass-covered  sur- 
face of  the  lawn,  which  was  here  inclined  at 
an  angle  of  16°  20',*  nevertheless  many  par- 


Chap.  VI.  AIDED   BY   WORMS.  273 

tides  of  the  chalk  were  found  three  inches 
below  the  casting.  The  experiment  was  re- 
peated on  three  other  castings  on  different 
parts  of  the  lawn,  which  sloped  at  2°  30', 
3°  and  6°;  and  particles  of  chalk  could  be 
seen  between  4  and  5  inches  below  the  cast- 
ing ;  and  after  the  surface  had  become  dry, 
particles  were  found  in  two  cases  at  a  distance 
of  5  and  6  inches.  Several  other  castings 
with  precipitated  chalk  placed  on  their 
summits  were  left  to  the  natural  action  of 
the  rain.  In  one  case,  after  rain  which  was 
not  heavy,  the  casting  was  longitudinally 
streaked  with  white.  In  two  other  cases  the 
surface  of  the  ground  was  rendered  some- 
what white  for  a  distance  of  one  inch  from 
the  casting  ;  and  some  soil  collected  at  a  dis- 
tance of  2~  inches,  where  the  slope  was  7°_, 
effervesced  slightly  when  j)laced  in  acid. 
After  one  or  two  weeks,  the  chalk  was  wholly? 
or  almost  wholly  washed  away  from  all  the 
castings  on  which  it  had  been  placed,  and 
these  had  recovered  their  natural  colour. 

It  may  be  here  remarked  that  after  very 
heavy  rain  shallow  pools  may  be  seen  on  level 
or  nearly  level  fields,  where  the  soil  is  not 


274  DENUDATION   OF   THE   LAND     Chap.  YI. 

very  porous,  and  the  water  in  them  is  often 
slightly  muddy ;  when  such  little  pools  have 
dried,  the  leaves  and  hlades  of  grass  at  their 
bottoms  are  generally  coated  with  a  thin  layer 
of  mud.  This  mud  I  believe  is  derived  in 
large  part  from  recently  ejected  castings. 

Dr.  King  informs  me  that  the  majority  of 
the  before  described  gigantic  castings,  which 
he  found  on  a  fully  exposed,  bare,  gravelly 
knoll  on  the  Nilgiri  Mountains  in  India,  had 
been  more  or  less  weathered  by  the  previous 
north-east  monsoon  ;  and  most  of  them  pre- 
sented a  subsided  appearance.  The  worms 
here  eject  their  castings  only  during  the  rainy 
season  ;  and  at  the  time  of  Dr.  King's  visit  no 
rain  had  fallen  for  110  days.  He  carefully 
examined  the  ground  between  the  place 
where  these  huge  castings  lay,  and  a  little 
water-course  at  the  base  of  the  knoll,  and 
nowhere  was  there  any  accumulation  of  fine 
earth,  such  as  would  necessarily  have  been 
left  by  the  disintegration  of  the  castings  if 
they  had  not  been  wholly  removed.  He 
Ihei'ofore  has  no  hesitation  in  asserting  that 
the  whole  of  these  huge  castings  are  annually 
washed    during    the    two    monsoons    (when 


CiiAP.  VI.  AIDED   BY   WORMS.  275 

about  100  inches  of  rain  fall)  into  the  little 
water-course,  and  thence  into  the  plains 
lying  below  at  a  depth  of  3000  or  4000  feet. 

Castings  ejected  before  or  during  dry 
weather  become  hard,  sometimes  surprisingly 
hard^  from  the  particles  of  earth  having  been 
cemented  together  by  the  intestinal  secre- 
tions. Frost  seems  to  be  less  effective  in 
their  disintegration  than  might  have  been 
expected.  Nevertheless  they  readily  disin- 
tegrate into  small  pellets,  after  being  alter- 
nately moistened  with  rain  and  again  dried. 
Those  which  have  flowed  during  rain  down  a 
slope,  disintegrate  in  the  same  manner.  Such 
pellets  often  roll  a  little  down  any  sloping 
surface ;  their  descent  being  sometimes  much 
aided  by  the  wind.  The  whole  bottom  of  a 
broad  dry  ditch  in  my  grounds,  where  there 
were  very  few  fresh  castings,  was  completely 
covered  with  these  pellets  or  disintegrated 
castings,  which  had  rolled  down  the  steep 
sides,  inclined  at  an  angle  of  27°. 

Near  Nice,  in  places  where  the  great  cylin- 
drical castings,  previously  described,  abound, 
the  soil  consists  of  very  fine  arenaceo-cal- 
careous  loam ;  and  Dr.  King  informs  me  that 


276  DENUDATION   OF   THE   LAND     Chap.  YI. 

these  castings  are  extremely  liable  to  crumble 
during  dry  weather  into  small  fragments^ 
which  are  soon  acted  on  by  rain,  and  then 
sink  down  so  as  to  be  no  longer  distinguisli* 
able  from  the  surrounding  soil.  He  sent  me 
a  mass  of  such  disintegrated  castings,  collected 
on  the  top  of  a  bank,  where  none  could  have 
rolled  down  from  above.  They  must  have 
been  ejected  within  the  previous  five  or  six 
months,  but  they  now  consisted  of  more  or  less 
rounded  fragments  of  all  sizes,  from  |-  of  an 
inch  in  diameter  to  minute  grains  and  mere 
dust.  Dr.  King  witnessed  the  crumbling 
process  whilst  drying  some  perfect  castings, 
which  he  afterwards  sent  me.  Mr.  Scott  also 
remarks  on  the  crumbling  of  the  castings 
near  Calcutta  and  on  the  mountains  of 
Sikkim  during  the  hot  and  dry  season. 

When  the  castings  near  Nice  had  been 
ejected  on  an  inclined  surface,  the  disinteg- 
rated fragments  rolled  downwards,  without 
losing  their  distinctive  shape  ;  and  in  som« 
places  could  "  be  collected  in  basketfuls."  Dr. 
King  observed  a  striking  instance  of  this  fact 
on  the  Corniche  road,  where  a  drain,  about 
2^  feet  wide  and  9  inches  deep,  had  been  made 


Chap.  Y1.  AIDED   BY   WOEMS.  277 

to  catch  tlie  surface  drainage  from  the  adjoin- 
ing hill-side.  The  bottom  of  this  drain  was 
covered  for  a  distance  of  several  hundred 
yarc's,  to  a  depth  of  from  1^  to  3  inches,  by  a 
layer  of  broken  castings,  still  retaining  their 
characteristic  shape.  Nearly  all  these  in- 
numerable fragments  had  rolled  down  from 
above,  for  extremely  few  castings  had  been 
ejected  in  the  drain  itself.  The  hill-side  was 
steep,  but  varied  much  in  inclination,  which 
Dr.  King  estimated  at  from  30^  to  60°  with 
the  horizon.  He  climbed  up  the  slope,  and 
"  found  every  here  and  there  little  embank- 
"  ments,  formed  by  fragments  of  the  castings 
"  that  had  been  arrested  in  their  downward 
"  progress  by  irregularities  of  the  surface, 
"by  stones,  twigs,  &c.  One  little  group  of 
''  plants  of  Anemone  hortensis  had  acted  in  this 
"  manner,  and  quite  a  small  bank  of  soil  had 
"collected  round  it.  Much  of  this  soil  had 
"crumbled  down,  but  a  great  deal  of  it  still 
"  retained  the  form  of  castings."  Dr.  King 
dug  up  this  plant,  and  was  struck  with 
the  thickness  of  the  soil  which  must  have 
recently  accumulated  over  the  crown  of  the 
rhizoma,    as    shown    by   the    length    of  the 


278  DENUDATION   TO   LAND  Chap.  \L 

bleached  petioles,  in  comparison  with  those 
of  other  plants  of  the  same  kind,  where 
there  had  been  no  such  accumulation.  The 
earth  thus  accumulated  had  no  doubt  been 
secured  (as  I  have  everywhere  seen)  by  the 
smaller  roots  of  the  plants.  After  describing 
this  and  other  analogous  cases,  Dr.  King  con- 
cludes :  "  I  can  have  no  doubt  that  worms 
"  help  greatly  in  the  process  of  denudation." 

Ledges  of  earth  on  steep  hill-sides. — Little 
horizontal  ledges,  one  above  another,  have  been 
observed  on  steep  grassy  slopes  in  many  parts 
of  the  world.  Their  formation  has  been 
attributed  to  animals  travelling  repeatedly 
along  the  slope  in  the  same  horizontal  lines 
while  grazing,  and  that  they  do  thus  move  and 
use  the  ledges  is  certain ;  but  Professor  Hens- 
low  (a  most  careful  observer)  told  Sir  J.  Hooker 
that  he  was  convinced  that  this  was  not  the 
sole  cause  of  their  formation.  Sir  J.  Hooker 
saw  such  ledges  on  the  Himalayan  and  Atlas 
ranges,  where  there  were  no  domesticated 
animals  and  not  many  wild  ones  ;  but  these 
latter  would,  it  is  probable,  use  the  ledges  at 
flight  while  grazing  like  our  domesticated 
nnimals,     A  friend  observed  for  me  the  ledges 


Chap.  YL  LEDGES   ON   HILL-SIDES.  279 

on  the  Alps  of  Switzerland,  and  states  thai 
they  ran  at  3  or  4  ft.  one  above  the  other 
and  were  about  a  foot  in  breadth.  They  had 
been  deeply  pitted  by  the  feet  of  grazing  cows. 
Similar  ledges  were  observed  by  the  same 
friend  on  our  Chalk  downs,  and  on  an  old 
talus  of  chalk-fragments  (thrown  out  of  a 
quarry)  which  had  become  clothed  with  turf. 
My  son  Francis  examined  a  Chalk  escarp- 
ment near  Lewes ;  and  here  on  a  part  which 
was  very  steep,  sloping  at  40°  with  the 
horizon,  about  30  flat  ledges  extended  hori- 
zontally for  more  than  100  yards,  at  an  average 
distance  of  about  20  inches,  one  beneath  the 
other.  They  were  from  9  to  10  inches  in 
breadth.  When  viewed  from  a  distance  they 
presented  a  striking  appearance,  owing  to  their 
parallelism ;  but  when  examined  closely,  they 
were  seen  to  be  somewhat  sinuous,  and  one 
often  ran  into  another,  giving  the  appearance 
of  one  ledge  having  forked  into  two.  They 
are  formed  of  light-coloured  earth,  which  on 
Ihe  outside,  where  thickest,  was  in  one  case  9 
inches,  and  in  another  case  between  6  and  7 
inches  in  thickness.  Above  the  ledges,  the 
thickness  of  the  earth  over  the  chalk  was  in 

19 


280  DENUDATION   TO   LAND  Chap.  VL 

the  former  case  4  and  in  the  latter  only  3 
inches.  The  grass  grew  more  vigorously  on 
the  outer  edges  of  the  ledges  than  on  any 
other  part  of  the  slope,  and  here  formed  a 
tufted  fringe.  Their  middle  part  was  bare,  but 
whether  this  had  been  caused  by  the  trampling 
of  sheep,  which  sometimes  frequent  the  ledges, 
my  son  could  not  ascertain.  Nor  could  he 
feel  sure  how  much  of  the  earth  on  the  middle 
and  bare  parts,  consisted  of  disintegrated 
worm-castings  which  had  rolled  down  from 
above;  but  he  felt  convinced  that  some  had 
thus  originated  ;  and  it  was  manifest  that  the 
ledges  with  their  grass-fringed  edges  would 
arrest  any  small  object  rolling  down  from 
above. 

At  one  end  or  side  of  the  oank  bearing 
these  ledges,  the  surface  consisted  in  parts  of 
bare  chalk,  and  here  the  ledges  were  very 
irregular.  At  the  other  end  of  the  bank,  the 
slope  suddenly  became  less  steep,  and  here  the 
ledges  ceased  rather  abruptly ;  but  little  em- 
bankments only  a  foot  or  two  in  length  were 
still  present.  The  slope  became  steeper  lower 
down  the  hill,  and  the  regular  ledges  then  re- 
appeared.    Another  of  my  sons  observed,  on 


Chap.  YI.  LEDGES   ON   HILL-SIDES.  281 

the  inland  side  of  Beachy  Head,  where  the 
surface  sloped  at  about  25°,  many  short  little 
embankments  like  those  just  mentioned. 
They  extended  horizontally  and  were  from  a 
few  inches  to  two  or  three  feet  in  length. 
They  supported  tufts  of  grass  growing 
vigorously.  The  average  thickness  of  the 
mould  of  which  they  were  formed,  taken 
from  nine  measurements,  was  4' 5  inches; 
while  that  of  the  mould  above  and  beneath 
them  was  on  an  average  only  3*2  inches,  and 
on  each  side,  on  the  same  level,  3'1  inches. 
On  the  upper  parts  of  the  slope,  these  em- 
bankments showed  no  signs  of  having  been 
trampled  on  by  sheep,  but  in  the  lower  parts 
such  signs  were  fairly  plain.  No  long  con- 
tinuous ledges  had  here  been  formed. 

If  the  little  embankments  above  the  Cor- 
niche  road,  which  Dr.  King  saw  in  the  act 
of  formation  by  the  accumulation  of  dis- 
integrated and  rolled  worm-castings,  were  to 
become  confluent  along  horizontal  lines,  ledges 
would  be  formed.  Each  embankment  would 
tend  to  extend  laterally  by  the  lateral  extension 
of  the  arrested  castings;  and  animals  grazing  on 
a  steep  slope  would  almost  certainly  make  use 


282  DENUDATION   TO   LAND  Chap.  Yl 

of  every  prominence  at  nearly  the  same  level, 
and  would  indent  the  turf  between  them  ;  and 
such  intermediate  indentations  would  again 
arrest  the  castings.  An  irregular  ledge  when 
once  formed  would  also  tend  to  become  more 
regular  and  horizontal  by  some  of  the  castings 
rolling  laterally  from  the  higher  to  the  lower 
parts,  which  would  thus  be  raised.  Any  pro- 
jection beneath  a  ledge  would  not  afterwards 
receive  distintegrated  matter  from  above, 
and  would  tend  to  be  obliterated  by  rain  and 
other  atmospheric  agencies.  There  is  some 
analogy  between  the  formation,  as  here  sup- 
posed, of  these  ledges,  and  that  of  the  ripples 
of  wind-drifted  sand  as  described  by  Lyell.* 

The  steep,  grass-covered  sides  of  a 
mountainous  valley  in  Westmoreland,  called 
G-risedale,  was  marked  in  many  places  with 
innumerable,  almost  horizontal,  little  ledges, 
or  rather  lines  of  miniature  cliffs.  Their 
formation  was  in  no  way  connected  with  the 
action  of  worms,  for  castings  could  not  any- 
wiiere  be  seen  (and  their  absence  is  an 
inexplicable  fact)  although  the  turf  lay  in 
many  places  over  a  considerable  thickness  of 

*  '  Elements  of  Geology,'  18G5,  p.  20 


Chap.  YI.  LEDGES   ON   HILL-SIDES.  283 

boulder-clay  and  moraine  rubbish.  Nor,  as 
far  as  I  could  judge,  was  the  formation  of 
these  little  cliffs  at  all  closely  connected  with 
the  trampling  of  cows  or  sheep>  It  appeared 
as  if  the  whole  superficial,  somewhat  argil- 
laceous earth,  while  partially  held  together 
by  the  roots  of  the  grasses,  had  slided  a  little 
way  down  the  mountain  sides ;  and  in  thus 
sliding,  had  yielded  and  cracked  in  horizontal 
lines,  transversely  to  the  slope. 

Castings  blown  to  leevjard  by  the  wind, — We 
have  seen  that  moist  castings  flow,  and  that 
disintegrated  castings  roll  down  any  inclined 
surface ;  and  we  shall  now  see  that  castings, 
recently  ejected  on  level  grass-covered 
surfaces,  are  blown  during  gales  of  wind  ac- 
companied by  rain  to  leeward.  This  has  been 
observed  by  me  many  times  on  many  fields 
during  several  successive  years.  After  such 
gales,  the  castings  present  a  gently  inclined 
and  smooth,  or  sometimes  furrowed,  surface 
to  windward,  while  they  are  steeply  inclined 
or  precipitous  to  leeward,  so  that  they  resem- 
ble on  a  miniature  scale  glacier-groimd  hillocks 
of  rock.      They  are  often  cavernous   on  the 


284-  DENUDATION   OF   THE   LAND.     Chap.  VL 

leeward  side,  from  the  upper  part  having 
curled  over  the  lower  part.  During  one  un- 
usually heavy  south-west  gale  with  torrents 
of  rain,  many  castings  were  wholly  blown  to 
leeward,  so  that  the  mouths  of  the  burrows 
were  left  naked  and  exposed  on  the  windward 
side.  Eecent  castings  naturally  flow  down 
an  inclined  surface,  but  on  a  grassy  field, 
which  sloped  between  10°  and  15°,  several 
were  found  after  a  heavy  gale  blown  up  the 
slope.  This  likewise  occurred  on  another 
occasion  on  a  part  of  my  lawn  where  the 
slope  was  somewhat  less.  On  a  third  occasion, 
the  castings  on  the  steep,  grass-covered  sides 
of  a  valley,  down  which  a  gale  had  blown, 
were  directed  obliquely  instead  of  straight 
down  the  slope  ;  and  this  was  obviously  due 
to  the  combined  action  of  the  wind  and 
gravity.  Four  castings  on  my  lawn,  where 
the  downward  inclination  was  0°  45',  1°,  3°  and 
3°  30'  (mean  2°  45')  towards  the  north-cast, 
after  a  heavy  south-west  gale  with  rain,  were 
divided  across  the  mouths  of  the  burrows  and 
weighed  in  the  manner  formerly  described. 
The  mean  weight  of  the  earth  below  the 
mouths  of  burrows  and  to  leeward,  was  to  that 


Chap.  YI.      CASTINGS   BLOWN   TO   LEEWAKD.      2S5 

above  tlie  nQOuths  and  on  the  windward  side 
as  2|  to  1  ;  whereas  we  have  seen  that  with 
several  castings  which  had  flowed  down  slopes 
having  a  mean  inchnation  of  9°  26',  and  with 
three  castings  where  the  inclination  was 
above  12°,  the  proportional  weight  of  the 
earth  below  to  that  above  the  burrows  was 
as  only  2  to  1.  These  several  cases  show  how 
efficiently  gales  of  wind  accompanied  by  rain 
act  in  displacing  recently-ejected  castings. 
We  may  therefore  conclude  that  even  a 
moderately  strong  wind  will  produce  some 
slight  effect  on  them. 

Dry  and  indurated  castings,  after  their  dis- 
integration into  small  fragments  or  pellets,  are 
sometimes,  probably  often,  blown  by  a  strong 
wind  to  leeward.  Thk  was  observed  on  four 
occasions,  but  I  did  not  sufficiently  attend  to 
this  point.  One  old  casting  on  a  gently  slop- 
ing bank  was  blown  quite  away  by  a  strong 
south-west  wind.  Dr.  King  believes  that 
the  wind  removes  the  greater  part  of  the 
old  crumbling  castings  near  Nice.  Several 
old  castings  on  my  lawn  were  marked  with 
pins  and  protected  from  any  disturbance. 
They  were  examined  after  an  interval  of  10 


286  DENUDATION  OF   THE   LAND.     Chap.  YI, 

weeks,  duriog  wbicli  time  the  weather  had 
been  alternately  dry  and  rainy.  Some,  which 
were  of  a  yellowish  colour  had  been  washed 
almost  completely  away,  as  could  be  seen 
by  the  colour  of  the  surrounding  ground. 
Others  had  completely  disappeared,  and  these 
no  doubt  had  been  blown  away.  Lastly, 
others  still  remained  and  would  long  remain, 
as  blades  of  grass  had  grown  through  them. 
On  poor  pasture  land,  which  has  never  been 
rolled  and  has  not  been  much  trampled  on 
by  animals,  the  whole  surface  is  sometimes 
dotted  with  little  pimples,  through  and  on 
which  grass  grows ;  and  these  pimples  con- 
sist of  old  worm-castings. 

In  all  the  many  observed  cases  of  soft  cast- 
ings blown  to  leeward,  this  had  been  effected 
by  strong  winds  accompanied  by  rain.  As 
such  winds  in  England  generally  blow  from 
the  south  and  south-west,  earth  must  on  the 
whole  tend  to  travel  over  our  fields  in  a 
north  and  north-east  direction.  This  fact  is 
interesting,  because  it  might  be  thought  that 
none  could  be  removed  from  a  level,  grass- 
covered  surface  by  any  means.  In  thick  and 
level  woods,  protected  from  the  wind,  castings 


Chap.  VI.      CASTINGS   BLOWN   TO   LEEWAED.     287 

will  never  be  removed  as  long  as  tlie  wood 
lasts ;  and  mould  will  here  tend  to  accumulate 
to  the  depth  at  which  worms  can  work,  I 
tried  to  procure  evidence  as  to  how  much 
mould  is  blown,  whilst  in  the  state  of  cast/- 
ings,  by  our  wet  southern  gales  to  the  north- 
east, over  open  and  flat  land,  by  looking  to 
the  level  of  the  surface  on  opposite  sides  of 
old  trees  and  hedge-rows ;  but  1  failed  owing 
to  the  unequal  growth  of  the  roots  of  trees 
and  to  most  pasture-land  having  been  formerly 
ploughed. 

On  an  open  plain  near  Stonehenge,  there 
exist  shallow  circular  trenches,  with  a  low 
embankment  outside,  surrounding  level  spaces 
50  yards  in  diameter.  These  rings  appear 
very  ancient,  and  are  believed  to  be  contem 
poraneous  with  the  Druidical  stones.  Castings 
ejected  within  these  circular  spaces,  if  blown 
to  the  north-east  by  south-west  winds  would 
form  a  layer  of  mould  within  the  trench, 
thicker  on  the  north-eastern  than  on  any  other 
side.  But  the  site  was  not  favourable  for  the 
action  of  worms,  for  the  mould  over  the 
surrounding  Chalk  formation  with  flints,  was 
only  3*37  inches  in  thickness,  from  a  mean  of 


288  DENUDATION   OF   THE   LAND.     Chap.  VL 

six  observations  made  at  a  distance  of  10  yards 
outside  the  embankment.  The  thickness  of 
the  mould  within  two  of  the  circular  trenches 
was  measured  every  5  yards  all  round,  on  the 
inner  sides  near  the  bottom.  My  son  Horace 
protracted  these  measurements  on  paper  ;  and 
though  the  curved  line  representing  the  thick- 
ness of  the  mould  was  extremely  irregular,  yet 
in  both  diagrams  it  could  be  seen  to  be  thicker 
on  the  north-eastern  side  than  elsewhere. 
When  a  mean  of  all  the  measurements  in  both 
the  trenches  was  laid  down  and  the  line 
smoothed,  it  was  obvious  that  the  mould  was 
thickest  in  the  quarter  of  the  circle  between 
nortli-west  and  north-east;  and  thinnest  in 
the  quarter  between  south-east  and  south- 
west, especially  at  this  latter  point.  Besides 
the  foregoing  measurements,  six  others  were 
taken  near  together  in  one  of  the  circular 
trenches,  on  the  north-east  side ;  and  the 
mould  here  had  a  mean  thickness  of  2*29 
inches ;  while  the  mean  of  six  other  measure- 
ments on  the  south-west  side  was  only  1*46 
inches.  These  observations  indicate  that  the 
castings  had  been  blown  by  the  south-west 
winds  from  the  circular  enclosed  space  into 


Chap.  VI.      CASTINGS  BLOWN   TO   LEEWARD.      289 

the  trencli  on  the  north-east  side  ;  but  many 
more  measurements  in  other  analogous  cases 
would  be  requisite  for  a  trustworthy  result. 

The  amount  of  fine  earth  brought  to  the 
surface  under  the  form  of  castings,  and  after- 
wards transported  by  the  winds  accompanied 
by  rain,  or  that  which  flows  and  rolls  down 
an  inclined  surface,  no  doubt  is  small  in  the 
course  of  a  few  scores  of  years ;  for  otherwise 
all  the  inequalities  in  our  pasture  fields  Tvould 
be  smoothed  within  a  much  shorter  period 
than  appears  to  be  the  case.  But  the  amount 
which  is  thus  transported  in  the  course  of 
thousands  of  years  cannot  fail  to  be  consider- 
able and  deserves  attention.  E.  de  Beaumont 
looks  at  the  vegetable  mould  which  every- 
where covers  the  land  as  a  fixed  line  or  zero, 
from  which  the  amount  of  denudation  may 
be  measured.*  He  ignores  the  continued 
formation  of  fresh  mould  by  the  disintegra- 
tion of  the  underlying  rocks  and  fragments  of 
rock ;  and  it  is  curious  to  find  how  much 
more    philosophical    were   the   views,    main- 

*  "  Lecons  de  Geologie  pratique,  1845  ;  cinqiiieme  Le9on. 
All  Elie  de  Beaumont's  arguments  are  admirably  controverted 
by  Prof.  A.  Geikie  in  his  essay  in  Transact.  Geolog.  Soc.  of 
Glasgow,  vol.  iii.  p.  153,  1868. 


290  DENUDATION   OF   THE   LAND.     Chap.  VL 

tallied  long  ago,  by  Playfair,  who,  in  1802, 
wrote,  *'  in  the  permanence  of  a  coat  of 
''  vegetable  mould  on  the  surface  of  the  earth, 
"  we  have  a  demonstrative  proof  of  the  con- 
"  tinned  destruction  of  the  rocks."* 

Ancient  encampments  and  tumuli, — E.  de 
Beaumont  adduces  the  present  state  of  many 
ancient  encampments  and  tumuli  and  of  old 
ploughed  fields,  as  evidence  that  the  surface 
of  the  land  undergoes  hardly  any  degradation. 
But  It  does  not  appear  that  he  ever  examined 
the  thickness  of  the  mould  over  different 
parts  of  such  old  remains.  He  relies  chiefly 
on  indirect,  but  apparently  trustworthy,  evi- 
dence that  the  slopes  of  the  old  embankments 
are  the  same  as  they  originally  were  ;  and  it 
is  obvious  that  he  could  know  nothing  about 
their  original  heights.  In  Knole  Park  a 
mound  had  been  thrown  up  behind  the  rifle- 
targets,  which  appeared  to  have  been  formed 
of  earth  originally  supported  by  square  blocks 
of  turf.  The  sides  sloped,  as  nearly  as  I  could 
estimate  them,  at  an  angle  of  45°  or  50°  with 
the  horizon,  and  they  were  covered,  especially 
on  the  northern  side,  with  long  coarse  grass, 

•  'Illustrations  of  the  Iluttonian  Theory  of  the  Earth/ p.  107, 


CiiAi'.  YI.  ANCIENT   MOUNDS.  291 

beneath  which  many  worm-castings  were 
found.  These  had  flowed  bodily  downwards^ 
and  others  had  rolled  down  as  pellets.  Hence 
it  is  certain  that  as  long  as  a  mound  of  thia 
kind  is  tenanted  by  worms,  its  height  will  be 
continually  lowered.  The  fine  earth  which 
flows  or  rolls  down  the  sides  of  such  a  mound 
accumulates  at  its  base  in  the  form  of  a  talus. 
A  bed,  even  a  very  thin  bed,  of  fine  earth  is 
eminently  favourable  for  worms ;  so  that  a 
greater  Dumber  of  castings  would  tend  to  be 
ejected  on  a  talus  thus  formed  than  elsewhere  : 
and  these  would  be  partially  washed  away  by 
every  heavy  shower  and  be  spread  over  the 
adjoining  level  ground.  The  final  result 
would  be  the  lowering  of  the  whole  mound, 
whilst  the  inclination  of  the  sides  would  not 
be  greatly  lessened.  The  same  result  would 
assuredly  follow  with  ancient  embankments 
and  tumuli ;  except  where  they  had  been 
formed  of  gravel  or  of  nearly  pure  sand,  as  such 
matter  is  unfavourable  for  worms.  Many  old 
fortifications  and  tumuli  are  believed  to  be  at 
least  2000  years  old ;  and  we  should  bear  in 
mind  that  in  many  places  about  one  inch  of 
mould  is  brought  to  the  surface  in  5  years  or 


292  DENUDATION   OF   THE   LAND.     Chap.  VL 

two  inches  in  10  years.  Therefore  in  so  long 
a  period  as  2000  years,  a  large  amount  of 
earth  will  have  been  repeatedly  brought  to 
the  surface  on  most  old  embankments  and 
tumuli,  especially  on  the  talus  round  their 
bases,  and  much  of  this  earth  will  have  been 
washed  completely  away.  We  may  therefore 
conclude  that  all  ancient  mounds,  when  not 
formed  of  materials  unfavourable  to  worms, 
will  have  been  somewhat  lowered  in  the 
course  of  centuries,  although  their  inclina- 
tions may  not  have  been  greatly  changed. 

Fields  formerly  ploughed, — From  a  very 
remote  period  and  in  many  countries,  land 
has  been  ploughed,  so  that  convex  beds, 
called  crowns  or  ridges,  usually  about  8  feet 
across  and  separated  by  furrows,  have  been 
thrown  up.  The  furrows  are  directed  so  as 
to  carry  off  the  surface  water.  In  my 
attempts  to  ascertain  how  long  a  time  these 
crowns  and  furrows  last,  when  ploughed  land 
has  been  converted  into  pasture,  obstacles  of 
many  kinds  were  encountered.  It  is  rarely 
known  when  a  field  was  last  ploughed  ;  and 
some  fields  which  were  thought  to  have  been 
in  pasture  from  time  immemorial  were  after 


Chap.  VI.      ANCIENTLY   PLOUGHED   FIELDS.        293 

wards  discovered  to  have  been  ploughed  only 
50  or  60  years  before.  During  the  early 
part  of  the  present  century,  when  the  price 
of  corn  was  very  high,  land  of  all  kinds  seema 
to  have  been  ploughed  in  Britain.  There  is, 
however,  no  reason  to  doubt  that  in  many 
eases  the  old  crowns  and  furrows  have  been 
preserved  from  a  very  ancient  period.*  That 
they  should  have  been  preserved  for  very 
unequal  lengths  of  time  would  naturally 
follow  from  the  crowns,  when  first  thrown 
up,  having  differed  much  in  height  in  dif- 
ferent districts,  as  is  now  the  case  with 
recently  ploughed  land. 

In  old  pasture  fields,  the  mould,  wherever 
measurements  were  made,  was  found  to  be 
from  i  to  2  inches  thicker  in  the  furrows  than 

*  Mr.  E.  Tylor  in  his  Presidential  address  ('Jouraal  of  the 
Anthropological  Institute,'  May  1880,  p.  451)  remarks:  "It 
appears  from  several  papers  of  the  Berlin  Society  as  to  tho 
German  'high-fields'  or  'heathen-fields*  (Eochacker,  and 
Heidenacker)  that  they  correspond  much  in  their  situation  on  hills 
and  wastes  with  the  '  elf-furrows '  of  Scotland,  which  popular 
mythology  accounts  for  by  the  story  of  the  fields  having  been 
put  under  a  Papal  interdict,  so  that  people  took  to  cultivating 
the  hills.  There  seems  reason  to  suppose  that,  like  the  tilled 
plots  in  the  Swedish  forests  which  tradition  ascribes  to  the  Did 
'  hackers,*  the  German  heathen-fields  represent  tillage  by  an 
ancient  and  barbaric  population." 


294  DENUDATION   OF   TEE   LAND.     Chap.  VI 

on  tlie  crowns ;  but  this  would  naturally 
follow  from  the  finer  earth  having  been 
washed  from  the  crowns  into  the  furrows 
before  the  land  was  well  clothed  with  turf; 
and  it  is  impossible  to  tell  what  part  worms 
may  have  played  in  the  work.  Nevertheless 
from  what  we  have  seen,  castings  would 
certainly  tend  to  flow  and  to  be  washed  during 
heavy  rain  from  the  crowns  into  the  furrows. 
But  as  soon  as  a  bed  of  fine  earth  had  by  any 
means  been  accumulated  in  the  furrows,  it 
would  be  more  favourable  for  worms  than  the 
other  parts,  and  a  greater  number  of  castings 
would  be  thrown  up  here  than  elsewhere  ;  and 
as  the  furrows  on  sloping  land  are  usually 
directed  so  as  to  carry  off  the  surface  water, 
some  of  the  finest  earth  would  be  washed 
from  the  castings  which  had  been  here  ejected 
and  be  carried  completely  away.  The  result 
would  be  that  the  furrows  would  be  filled 
up  very  slowly,  while  the  crowns  would  be 
lowered  perhaps  still  more  slowly  by  the 
flowing  and  rolling  of  the  castings  down 
their  gentle  inclinations  into  the  furrows. 

Nevertheless  it  might  be  expected  that  old 
furrows,  especially  those  on  a  sloping  surface, 


Chap.  VI.      ANCIENTLY   PLOUGHED   FIELDS.        295 

would  in  the  course  of  time  be  filled  up  and 
disappear.  Some  careful  observers,  however, 
who  examined  fields  for  me  in  Grloucestershire 
and  Staffordshire,  could  not  detect  any  dif- 
ference in  the  state  of  the  furrows  in  the 
upper  and  lower  parts  of  sloping  fields,  sup- 
posed to  have  been  long  in  pasture  ;  and  they 
came  to  the  conclusion  that  the  crowns  and 
furrows  would  last  for  an  almost  endless 
number  of  centuries.  On  the  other  hand  the 
process  of  obliteration  seems  to  have  com- 
menced in  some  places.  Thus  in  a  grass 
field  in  North  Wales,  known  to  have  been 
ploughed  about  65  years  ago,  which  sloped  at 
an  angle  of  15°  to  the  north-east,  the  depth 
of  the  furrows  (only  7  feet  apart)  was  care- 
fully measured,  and  was  found  to  be  about 
4^  inches  in  the  upper  part  of  the  slope,  and 
only  1  inch  near  the  base,  where  they  could 
be  traced  with  difficulty.  On  another  field 
sloping  at  about  the  same  angle  to  the  south- 
west, the  furrows  were  scarcely  perceptible 
in  the  lower  part ;  although  these  same 
furrows  when  followed  on  to  some  adjoining 
level  ground  were  from  2^  to  3^  inches  in 
depth.     A  third  and  closely  similar  case  was 

20 


296  DEi^UDATION   OF   THE   LAND.     Chap.  YI. 

observed.  In  a  fourth  case,  the  mould  in  a 
furrow  in  the  upper  part  of  a  sloping  field 
was  2^  inches,  and  in  the  lower  part  4| 
inches  in  thickness. 

On  the  Chalk  Downs  at  about  a  mile  dis- 
tance from  Stonehenge,  my  son  William  ex- 
amined a  grass-covered,  furrowed  surface, 
sloping  at  from  8°  to  10°,  which  an  old  shep- 
herd said  had  not  been  ploughed  within  the 
memory  of  man.  The  depth  of  one  furrow 
was  measured  at  16  points  in  a  length  of  68 
paces,  and  was  found  to  be  deeper  where  the 
slope  was  greatest  and  where  less  earth  would 
naturally  tend  to  accumulate,  and  at  the 
base  it  almost  disappeared.  The  thickness  of 
the  mould  in  this  furrow  in  the  upper  part 
was  2^  inches,  which  increased  to  5  inches  a 
little  aboA^e  the  steepest  part  of  the  slope ;  and 
at  the  base,  in  the  middle  of  the  narrow 
valley,  at  a  point  which  the  furrow  if  con- 
tinued would  have  struck,  it  amounted  to  7 
inches.  On  the  opposite  side  of  the  valley, 
there  were  very  faint,  almost  obliterated, 
traces  of  furrows.  Another  analogous  but 
not  so  decided  a  case  was  observed  at  a  few 
miles   distance    from   Stonehenge.      On   the 


Chap.  Y1.       MOULD  OYER  TEE   CHALK.  297 

whole  it  appears  that  the  crowns  and  fur- 
rows on  land  formerly  ploughed,  but  now 
covered  with  grass,  tend  slowly  to  disappear 
when  the  surface  is  inclined ;  and  this  is  pro- 
bably in  large  part  due  to  the  action  of 
worms ;  but  that  the  crowns  and  furrows  last 
for  a  very  long  time  when  the  surface  is 
nearly  level. 

Formation  and  amount  of  mould  over  the 
Chalk  Formation, — Worm-castings  are  often 
ejected  in  extraordinary  numbers  on  steep, 
grass-covered  slopes,  where  the  Chalk  comes 
close  to  the  surface,  as  my  son  William 
observed  near  Winchester  and  elsewhere.  If 
such  castings  are  largely  washed  away  during 
heavy  rains,  it  is  difficult  to  understand  at 
first  how  any  mould  can  still  remain  on  our 
Downs,  as  there  does  not  appear  any  evident 
means  for  supplying  the  loss.  There  is,  more- 
ovei,  another  cause  of  loss,  namely  in  the  per- 
colation of  the  finer  particles  of  earth  into  the 
fissures  in  the  chalk  and  into  the  chalk  itself. 
These  considerations  led  me  to  doubt  for  a  timo 
whether  I  had  not  exaggerated  the  amount 
of  fine  earth  which  flows  or  rolls  down  grass- 
covered  slopes  under  the  form  of  castings ;  and 


298  DENUDATION   OF  THE   LAND.     Chap.  VI. 

I  sougbt  for  additional  information.  In  some 
places,  the  castings  on  Chalk  Downs  consist 
largely  of  calcareous  matter,  and  here  the 
supply  is  of  course  unlimited.  But  in  other 
places,  for  instance  on  a  part  of  Teg  Down 
near  Winchester,  the  castings  were  all  black 
and  did  not  effervesce  with  acids.  The  mould 
over  the  chalk  was  here  only  from  3  to  4 
inches  in  thickness.  So  again  on  the  plain 
near  Stonehenge,  the  mould,  apparently  free 
from  calcareous  matter,  averaged  rather  less 
than  3^  inches  in  thickness.  "Why  worms 
should  penetrate  and  bring  up  chalk  in  some 
places  and  not  in  others  I  do  not  know. 

In  many  districts  where  the  land  is  nearly 
level,  a  bed  several  feet  in  thickness  of  red 
clay  full  of  unworn  flints  overlies  the  Upper 
Chalk.  This  overlying  matter,  the  surface 
of  which  has  been  converted  into  mould,  con 
sists  of  the  undissolved  residue  from  the  chalk. 
It  mav  be  well  here  to  recall  the  case  of  the 
fragments  of  chalk  buried  beneath  worm- 
castings  on  one  of  my  fields,  the  angles  of 
which  were  so  completely  rounded  in  the 
course  of  29  years  that  the  fragments  now 
resembled   water-worn    pebbles.     This   musl 


Chap.  VL       MOULD   OVER   THE   CHALK.  299 

have  been  effected  by  the  carbonic  acid  in 
the  rain  and  in  the  ground,  by  the  humus- 
acids,  and  by  the  corroding  power  of  living 
roots.*  Why  a  thick  mass  of  residue  has  not 
been  left  on  the  Chalk,  wherever  the  land  is 
nearly  level,  may  perhaps  be  accounted  for 
by  the  percolation  of  the  fine  particles  into 
the  fissures,  which  are  often  present  in  the 
chalk  and  are  either  open  or  are  filled  up 
with  impure  chalk,  or  into  the  solid  chalk 
itself.  That  such  percolation  occurs  can 
hardly  be  doubted.  My  son  collected  some 
powdered  and  fragmentary  chalk  beneath  the 
turf  near  Winchester  ;  the  former  was  found 
by  Colonel  Parsons,  R.E.,  to  contain  10  per 
cent.,  and  the  fragments  8  per  cent,  of  earthy 
matter.  On  the  flanks  of  the  escarpment  near 
Abinger  in  Surrey,  some  chalk  close  beneath 
a  layer  of  flints,  2  inches  in  thickness  and 
covered  by  8  inches  of  mould,  yielded  a  re- 
sidue of  3 '7  per  cent,  of  earthy  matter.  On 
the  other  hand  the  Upper  Chalk  properly 
contains,  as  I  was  informed  by  the  late  David 
Forbes  who  had  made  many  analyses,  only 
from  1  to  2  per  cent,  of  earthy  matter ;  and 
two  samples  from  pits  near  my  house  con- 


300  DENUDATION  OF   THE   LAND.     Chap.  VI 

tained  1*3  and  0*6  per  cent.  I  mention  these 
latter  cases  because,  from  the  thickness  of  the 
overlying  bed  of  red  clay  with  flints,  I  had 
imagined  that  the  underlying  chalk  liiight 
here  be  less  pure  than  elsewhere.  The  cause 
of  the  residue  accumulating  more  in  some 
places  than  in  others,  may  be  attributed  to  a 
layer  of  argillaceous  matter  having  been  left 
at  an  early  period  on  the  chalk,  and  this 
would  check  the  subsequent  percolation  of 
earthy  matter  into  it. 

From  the  facts  now  given  we  may  conclude 
that  castings  ejected  on  our  Chalk  Downs  suffer 
some  loss  by  the  percolation  of  their  finer 
matter  into  the  chalk.  But  such  impure 
superficial  chalk,  when  dissolved,  would  leave 
a  larger  supply  of  earthy  matter  to  be 
added  to  the  mould  than  in  the  case  of  pure 
chalk.  Besides  the  loss  caused  by  percola- 
tion, some  fine  earth  is  certainly  washed 
down  the  sloping  grass-covered  surfaces  of 
our  Downs.  The  washing-down  process,  how- 
ever, will  be  checked  in  the  course  of  time  ; 
for  although  I  do  not  know  how  thin  a  layer 
of  mould  suffices  to  support  worms,  yet  a  limit 
must  at  last  be  reached  ;  and  then  their  cast- 


Chap.  YI.       MOULD   OYEK   THE   CHALK.  301 

ings   would    cease   to   be    ejected    or   would 
become  scanty. 

The  following  cases  show  that  a  consider- 
able quantity  of  fine  earth  is  washed  down 
The  thickness  of  the  mould  was  measured  ai 
points  12  yards  apart  across  a  small  valley 
in  the  Chalk  near  Winchester.  The  sides 
sloped  gently  at  first ;  then  became  inclined 
at  about  20°  ;  then  more  gently  to  near  the 
bottom,  wdiich  transversely  was  almost  level 
and  about  50  yards  across.  In  the  bottom, 
the  mean  thickness  of  the  mould  from  five 
measurements  was  83  inches;  whilst  on  the 
sides  of  the  valley,  where  the  inclination 
varied  between  14°  and  20°,  its  mean  thick- 
ness was  rather  less  than  3*5  inches.  As  the 
turf-covered  bottom  of  the  valley  sloped  at  an 
angle  of  only  between  2°  and  3°,  it  is  probable 
that  most  of  the  8*3-inch  layer  of  mould  had 
been  washed  down  from  the  fianks  of  the 
valley,  and  not  from  the  upper  part.  But  as 
a  shepherd  said  that  he  had  seen  water  flow- 
ing in  this  valley  after  the  sudden  thawing  of 
snow,  it  is  possible  that  some  earth  may  have 
been  broTight  down  from  the  upper  part ;  or, 
on  the  other  hand,  that  some  may  have  been 


302  DENUDATION   OF   THE   LAND.     Chap.  YI. 

carried  further  down  the  valley.  Closely 
similar  results,  with  respect  to  the  thickness  of 
the  mould,  were  obtained  in  a  neighbouring 
valley. 

St.  Catherine's  Hill,  near  Winchester,  is 
827  feet  in  height,  and  consists  of  a  steep 
cone  of  chalk  about  i  of  a  mile  in  diameter. 
The  upper  part  was  converted  by  the  Romans, 
or,  as  some  think,  by  the  ancient  Britons,  into 
an  encampment,  by  the  excavation  of  a  deep 
and  broad  ditch  all  round  it.  Most  of  the 
chalk  removed  during  the  work  was  thrown 
upwards,  by  which  a  projecting  bank  was 
formed  ;  and  this  effectually  prevents  worm- 
castings  (which  are  numerous  in  parts),  stones, 
and  other  objects  from  being  washed  or  rolled 
into  the  ditch.  The  mould  on  the  upper  and 
fortified  part  of  the  hill  was  found  to  be  in 
most  places  only  from  2^  to  3^  inches  in 
thickness  ;  whereas  it  had  accumulated  at  the 
foot  of  the  embankment  above  the  ditch  to  a 
thickness  in  most  places  of  from  8  to  9^ 
iiiches.  On  the  embankment  itself  the  mould 
was  only  1  to  l^  inch  in  thickness;  and 
within  the  ditch  at  the  bottom  it  varied  from 
2|-  to  3|,  but  was  in  one  spot   6   inches   in 


Chap.  VI.       MOULD   OVEK   THE   CHALK.  303, 

thickness.  On  the  north-west  side  of  the 
hill,  either  no  embankment  had  ever  been 
thrown  up  above  the  ditch,  or  it  had  subse- 
quently been  removed  ;  so  that  here  there 
was  nothing  to  prevent  worm-castings,  earth 
and  stones  being  washed  into  the  ditch,  at  the 
bottom  of  which  the  mould  formed  a  layer 
from  11  to  22  inches  in  thickness.  It  should 
however  be  stated  that  here  and  on  other 
parts  of  the  slope,  the  bed  of  mould  often  con- 
tained fragments  of  chalk  and  flint  which 
had  obviously  rolled  down  at  different  times 
from  above.  The  interstices  in  the  under- 
lying fragmentary  chalk  were  also  filled  up 
with  mould. 

My  son  examined  the  surface  of  this  hill  to 
its  base  in  a  south-west  direction.  Beneath 
the  great  ditch,  where  the  slope  was  about 
24°.  the  mould  was  very  thin,  namely  from 
1|  to  2|  inches;  whilst  near  the  base,  where 
the  slope  was  only  3°  to  4°,  it  increased  to 
between  8  and  9  inches  in  thickness.  We 
may  therefore  conclude  that  on  this  artificially 
modified  hill,  as  well  as  in  the  natural  valleys 
of  the  neighbouring  Chalk  Downs,  some  fine 
earth,    probably  derived  in  large  part  from 


304  DENUDATION   OF   THE   LAND.     Chap.  VI. 

worm-castings,  is  washed  down,  and  accumu- 
lates in  the  lower  parts,  notwithstanding  the 
percolation  of  an  unknown  quantity  into  the 
underlying  chalk  ;  a  supply  of  fresh  earthy 
matter  being  afforded  by  the  dissolution  Ox 
the  chaJk  through  atmospheric  and  other 
agenoieis. 


CHAPTER  YII. 

COXCLUSIOX. 

Summary  of  the  part  which  worms  have  played  in  the  history 
of  the  world — Their  aid  in  the  disintegration  of  rocks — In  the 
denudation  of  the  land — In  the  preservation  of  ancient  remaina 
— In  the  preparation  of  the  soil  for  the  growth  of  plants — 
Mental  powers  of  worms — Concljsion. 

Worms  have  played  a  more  important  part 
in  the  history  of  the  world  than  most  persons 
would  at  first  suppose.  In  almost  all  humid 
countries  they  are  extraordinarily  numerous, 
and  for  their  size  possess  great  muscular 
power.  In  many  parts  of  England  a  weight 
of  more  than  ten  tons  (10,516  kilogrammes) 
of  dry  earth  annually  passes  through  their 
bodies  and  is  brought  to  the  surface  on  each 
acre  of  land ;  so  that  the  whole  superficial 
bed  of  vegetable  mould  passes  through  their 
bodies  in  the  course  of  every  few  years. 
From  the  collapsing  of  the  old  burrows  the 
mould  is  in  constant  though  slow  movement, 


306  CONCLUSION.  Chap.  VI 

and  the  particles  composing  it  are  thus 
rubbed  together.  By  these  means  fresh  sur- 
faces are  continually  exposed  to  the  action  of 
the  carbonic  acid  in  the  soil,  and  of  the 
humus-acids  which  appear  to  be  still  more 
efficient  in  the  decomposition  of  rocks.  The 
generation  of  the  humus-acids  is  probably 
hastened  during  the  digestion  of  the  many 
half-decayed  leaves  which  worms  consume. 
Thus  the  particles  of  earth,  forming  the 
superficial  mould,  are  subjected  to  conditions 
eminently  favourable  for  their  decomposition 
and  disintegration.  Moreover,  the  particles 
of  the  softer  rocks  suffer  some  amount  of 
mechanical  trituration  in  the  muscular  giz- 
zards of  worms,  in  which  small  stones  serve 
as  mill-stones. 

The  finely  levigated  castings,  when  brought 
to  the  surface  in  a  moist  condition,  flow  during 
rainy  weather  down  any  moderate  slope ;  and 
the  smaller  particles  are  washed  far  down 
even  a  gently  inclined  surface.  Castings 
when  dry  often  crumble  into  small  pellets 
and  these  are  apt  to  roll  down  any  sloping 
surface.  Where  the  land  is  quite  level  and 
is    covered    with    herbage,   and   where    tlio 


Chap.  YII.  CONCLUSION.  307 

climate  is  humid  so  that  much  dust  cannot  be 
blown  away  it  appears  at  first  sight  im- 
possible that  there  should  be  any  appreciable 
amount  of  subaerial  denudation ;  but  worm- 
castings  are  blown,  especially  whilst  moist 
and  viscid,  in  one  uniform  direction  by  the 
|.>revalent  winds  which  are  accompanied  by 
rain.  By  these  several  means  the  superficial 
mould  is  prevented  from  accumulating  to  a 
great  thickness ;  and  a  thick  bed  of  mould 
checks  in  many  ways  the  disintegration  of 
the  underlying  rocks  and  fragments  of  rock. 

The  removal  of  worm  castings  by  the  above 
means  leads  to  results  which  are  far  from 
insignificant.  It  has  been  shown  that  a 
layer  of  earth,  '2  of  an  inch  in  thickness,  is  in 
many  places  annually  brought  to  the  surface 
per  acre ;  and  if  a  small  part  of  this  amount 
flows,  or  rolls,  or  is  washed,  even  for  a  short 
distance  down  every  inclined  surface,  or  is 
repeatedly  blown  in  one  direction,  a  great 
effect  will  be  produced  in  the  course  of  ages. 
It  was  found  by  measurements  and  calculations 
that  on  a  surface  with  a  mean  inclination  of 
9°  26',  2*4  cubic  inches  of  earth  which  had 
been  ejected  by  worms  crossed,  in  the  course 


308  CONCLUSION,  Chap.  VIL 

of  a  year,  a  liorizontal  line  one  yard  in  length; 
so  that  240  cubic  inches  would  cross  a  line 
100  yards  in  length.  This  latter  amount  in  a 
damp  state  would  weigh  Hi  pounds.  Thus 
a  considerable  weight  of  earth  is  continually 
moving  down  each  side  of  every  valley,  and 
will  in  time  reach  its  bed.  Finally  this  earth 
will  be  transported  by  the  streams  flowing  in 
the  valleys  into  the  ocean,  the  great  receptacle 
for  all  matter  denuded  from  the  land.  It  is 
known  from  the  amount  of  sediment  annually 
delivered  into  the  sea  by  the  Mississippi,  that 
its  enormous  drainage-area  must  on  an  aver- 
age be  lowered  '00263  of  an  inch  each  year  ; 
and  this  would  suffice  in  four  and  half  million 
years  to  lower  the  whole  drainage-area  to  the 
level  of  the  sea-shore.  So  that,  if  a  small 
fraction  of  the  layer  of  fine  earth,  '2  of  an 
inch  in  thickness,  which  is  annually  brought 
to  the  surface  by  worms,  is  carried  away,  a 
great  result  cannot  fail  to  be  produced  within 
a  period  which  no  geologist  considers  ex- 
tremely long. 

Archaeologists     ought    to    be    grateful   to 
worms,  as  they  protect  and  preserve  for  an 


Chap.  VII.  CONCLUSION.  309 

indefinitely  long  period  every  object,  not 
liable  to  decay,  which  is  dropped  on  the 
surface  of  the  land,  by  burying  it  beneath 
their  castings.  Thus,  also,  many  elegant  and 
curious  tesselated  pavements  and  other  ancient 
remains  have  been  preserved ;  though  no 
doubt  the  worms  have  in  these  cases  been 
largely  aided  by  earth  washed  and  blown 
from  the  adjoining  land,  especially  when  cul- 
tivated. The  old  tesselated  pavements  have, 
however,  often  suffered  by  having  subsided 
unequally  from  being  unequally  undermined 
by  the  worms.  Even  old  massive  walls  may 
be  undermined  and  subside  ;  and  no  building 
is  in  this  respect  safe,  unless  the  foundations 
lie  6  or  7  feet  beneath  the  surface,  at  a  depth 
at  which  worms  cannot  work.  It  is  probable 
that  many  monoliths  and  some  old  walls  have 
fallen  down  from  having  been  undermined 
by  worms. 

Worms  prepare  the  ground  in  an  excellent 
manner  for  the  growth  of  fibrous-rooted 
plants  and  for  seedlings  of  all  kinds.  They 
peiiodically  expose  the  mould  to  the  air,  and 
sift  it  so  that  no  stones  larger  than  the  par- 


310  CONCLUSION.  Cbap.  YH 

tides  whicli  they  can  swallow  are  left  in  it 
They  mingle  the  whole  intimately  together, 
like  a  gardener  who  prepares  fine  soil  for  his 
choicest  plants.  In  this  state  it  is  well  fitted 
to  retain  moisture  and  to  absorb  all  soluble 
Bubsiances,  as  well  as  for  the  process  of  nitri- 
fication. The  bones  of  dead  animals,  the 
harder  parts  of  insects,  the  shells  of  land- 
molluscs,  leaves,  twigs,  (5^c.,  are  before  long 
all  buried  beneath  the  accumulated  castings  of 
worms,  and  are  thus  brouglit  in  a  more  or 
less  decayed  state  within  reach  of  the  roots 
of  plants.  Worms  likewise  drag  an  infinite 
number  of  dead  leaves  and  other  parts  of 
nlants  into  their  burrows,  partly  for  the  sake 
of  plugging  them  up  and  partly  as  food. 

The  leaves  which  are  dragged  into  the  bur- 
rows as  food,  after  being  torn  into  the  finest 
shreds,  partially  digested,  and  saturated  with 
the  intestinal  and  urinary  secretions,  are  com- 
mingled with  much  earth.  This  earth  forms 
the  dark  coloured,  rich  humus  which  almost 
everywhere  covers  the  surface  of  the  land 
with  a  fairly  well-defined  layer  or  mantle. 
"\^on  Hen  sen*  placed  two  worms  in  a  vessel 

♦  '  Zeitschrift  fiir  wissenschaft.  Zoolog.'  B,  xxviii.  1877,  p.  3B0. 


Chap.  VII  CONCLUSION.  311 

J  8  inches  in  diameter,  which  was  filled  with 
sand,  on  which  fallen  leaves  were  strewed ; 
and  these  were  soon  dragged  into  their  bur- 
rows to  a  depth  of  3  inches.  After  about  G 
weeks  an  almost  uniform  layer  of  sand,  a 
centimeter  ('4  inch)  in  thickness,  was  con- 
verted into  humus  by  having  passed  through 
the  alimentary  canals  of  these  two  worms. 
It  is  believed  by  some  persons  that  worm- 
burrows,  which  often  penetrate  the  ground 
almost  perpendicularly  to  a  depth  of  5  or  6 
feet,  materially  aid  in  its  drainage  ;  notwith- 
stsinding  that  the  viscid  castings  piled  over 
the  mouths  of  the  burrows  prevent  or  check 
the  rain-water  directly  entering  them.  They 
allow  the  air  to  penetrate  deeply  into  the 
ground.  They  also  greatly  facilitate  the 
downward  passage  of  roots  of  moderate  size  ; 
and  these  will  be  nourished  by  the  humus 
with  which  the  burrows  are  lined.  Many 
seeds  owe  their  germination  to  having  been 
covered  by  castings ;  and  others  buried  to 
a  considerable  depth  beneath  accumulated 
castings  lie  dormant,  until  at  some  future 
time  they  are  accidentally  uncovered  and 
germinate 
21 


312  CONCLUSION.  Chap.  VII. 

Worms  are  poorly  provided  with  sense- 
organs,  for  they  cannot  be  said  to  see, 
although  they  can  just  distinguish  between 
light  and  darkness  ;  they  are  completely  deaf, 
and  have  only  a  feeble  power  of  smell ;  the 
sense  of  touch  alone  is  well  developed.  They 
can  therefore  learn  little  about  the  outside 
world,  and  it  is  surprising  that  they  should 
exhibit  some  skill  in  lining  their  burrows 
with  their  castings  and  with  leaves,  and  in 
the  case  of  some  species  in  piling  up  their 
castings  into  tower-like  constructions.  But  it 
is  far  more  surprising  that  they  should  ap- 
parently exhibit  some  degree  of  intelligence 
instead  of  a  mere  blind  instinctive  impulse,  in 
their  manner  of  plugging,  up  the  mouths  of 
their  burrows.  They  act  in  nearly  the  same 
manner  as  would  a  man,  who  had  to  close  a 
cylindrical  tube  with  different  kinds  of  leaves, 
petioles,  triangles  of  paper,  &c.,  for  they 
commonly  seize  such  objects  by  their  pointed 
ends.  But  with  thin  objects  a  certain  number 
are  drawn  in  by  their  broader  ends.  They  do 
not  act  in  the  same  unvarying  manner  in  all 
cases,  as  do  most  of  the  lower  animals;  for 
instance,  they  do  not  drag  in  leaves  by  their 


Chap.  YII.  CONCLUSION.  313 

foot-stalks,  unless  the  basal  part  of  the  blade 
is  as  narrow  as  the  apex,  or  narrower  than  it. 

When  we  behold  a  wide,  turf-covered 
expanse,  we  should  remember  that  its  smooth- 
ness, on  which  so  much  of  its  beauty  depends, 
is  mainly  due  to  all  the  inequalities  having 
been  slowly  levelled  by  worms.  It  is  a  mar- 
vellous reflection  that  the  whole  of  the  super- 
ficial mould  over  any  such  expanse  has  passed, 
and  will  again  pass,  every  few  years  through 
the  bodies  of  worms.  The  plough  is  one  of 
the  most  ancient  and  most  valuable  of  man's 
inventions ;  but  long  before  he  existed  the 
land  was  in  fact  regularly  ploughed,  and  still 
continues  to  be  thus  ploughed  by  earth-worms. 
It  may  be  doubted  whether  there  are  many 
other  animals  which  have  played  so  important 
a  part  in  the  history  of  the  world,  as  have 
these  lowly  organised  creatures.  Some  other 
animals,  however,  still  more  lowly  organised, 
namely  corals,  have  done  far  more  conspicuous 
work  in  having  constructed  innumerable  reefs 
and  islands  in  the  great  oceans ;  but  these  are 
almost  confined  to  the  tropical  zones. 


INDEX. 


A-binger,  Eoman  villa  at,  178 

• castings    from    Roman    villa,    with     rounded 

particles,  258 
Acids  of  humus,  action  on  rocks,  240 
Africa,  dust  from,  235 
Air,  currents  of,  worms  sensitive  to,  28 
Amount  of  earth  brought  to  the  surface  by  worms,  129 
Ants,  intelligence  of,  93 
Archiac,  T)\  criticisms  on  my  views,  4 
Artemisia,  leaves  of,  not  eaten  by  worms,  33 
Ash-tree,  petioles  of,  79 

Beaulieu  Abbey,  burial  of  the  old  pavement,  193 

castings  from,  with   rounded   particles, 

255 

Beaumont,  ]6lie  de,  on  vegetable  mould,  2 

■        ' *^e   rubbish   underlying  great  cities, 

178 

the  transport  of  dust,  237 

■ ■  the  permanence  of  mould,  289 

the  permanence  of  ancient  tumuli,  290 


Beech-forests,  stones  not  buried  uuder  by  castings,  144 

Bengal,  worms  of,  123 

Bones,  crushed,  burial  of,  under  castings,  146 

Brading,  Koman  villa  at,  199 

,  castings  from,  with  rounded  particles,  264 


316  INDEX. 

Bridgman,  Mr.,  on  worms  eating  leaves  of  a  Phlox,  33 
Buckman,  on  grasses  profiting  by  being  rolled,  10 
Burial  of  the  remains  of  ancient    buildings  by  worms, 

176 
Burrows,  depth  of,  109 
direction  of,  on  a  slope,  270 

excavation  of,  98 

lined  with  black  earth,  111 

lined  with  leaves,  112 

mouths  of,  worms  lie  motionless  near,  15 

old,  their  collapse,  118 

— plugged  up,  58 

terminating  in  a  small  chamber,  often  lined  wit^h 

stones  or  seeds,  114 

Calciferous  glands,  17,  43 
Cannibal  worms,  36 
Carnagie,  Mr.,  depth  of  burrows,  114 
Castings,  acid,  52 

from  Beaulieu,  101 

■ tower-like,  near  Nice,  106 

ejection  of,  116 

tower-like,  from  near  Calcutta,  123 

of  great  size  on  the  Nilgiri  Mountains,  126 

weight  of,  from  a  single  burrow  and  from  a  given 

area,  160 

_ thickness  of  layer  formed  from,  during  a  year,  169 

ejected  over  ancient  buildings,  253 

flowing  down  slopes,  261 

washed  away,  272 

■ —  dry,  disintegration  of,  275 

blown  to  leeward,  283 


Cells,  free,   with   calcareous   matter   in   the   calciferous 

glands,  47 
Cellulose,  digestion  of,  37 


INDEX.  317 

Chalk-formation,  surface  of,  much  denuded,  137 
Clialk,  residue  of,  forming  a  superficial  deposit,  138 

fragments  of,  soon  buried  and  corroded,  139 

formation  of  mould  over,  297 

Ched worth,  Eoman  villa  of,  197 
Circular  trenches  near  Stonehenge,  287 
Claparede,  structure  of  the  intestines  of  worms,  19 

on  the  salivary  glands  of  worms,  42 

on  the  calciferous  glands,  44 

■ the  pharynx  adapted  for  suction,  56 

doubts  whether   earth  serves  worms  as  food,, 

102,  105 

on  the  gizzards  of  worms,  246 


Clematis,  petioles  of,  used  in  plugging  up  burrows,   58, 

77 
Cobra-snake,  intelligence  of,  94 
Collapsing  of  old  burrows,  118 
Concluding  remarks,  305 
Concretions  of  lime  in  the  anterior  calciferous  glands,  45* 

calcareous,  use  of,  54 

Corals,  mud  derived  from,  256 

Corniche  Eoad,  disintegrated  castings  on,  276,  281 

Croll,  Mr.,  on  denudation,  233 

Crowns  or  ridges  on  old  ploughed  fields,  292 

Currents  of  air,  worms  sensitive  to,  28 

Dancer,  Mr.,  on  the  action  and  number  of  worms,  146, 

159 
Deafness  of  worms,  26 

Debris,  over  the  Eoman  remains  at  Silchester,  201 
Decay  of  leaves  not  hastened  by  the  secretion  with  which 

they  are  bathed,  38 
I^enudation  of  the  land,  230 
Depth  to  which  worms  burrow,  109 
Ligaster,  246 


318  INDEX. 

Digestion  of  worms,  37 

exti  a-stomachal,  43 

Disintegration  of  rocks,  aided  by  worms,  240 

Distribution  of  worms,  120 

Down,   amount  of  earth  here  brought  annually  to   Uie 

surface,  137 
Downs  near  Winchester,  valleys  in,  301 
Dust,  distance  transported,  235-237 

Earth,  amount    of,  brought  to    the    surface    by   worms, 
129 

amount  of,  which  flows  down  a  given  slope,  266 

swallowed  as  food,  100 

weight  of,  ejected  from  a  single  burrow,  160 

Eisen,  number  of  species  of  worms,  9 

depth  of  burrows,  110 

Ejection  of  castings,  116 
Embankments  on  hill-sides,  278,  282 
Encampmeuts,  ancient,  290 
Ernst,  Dr.,  on  worms  at  Caracas,  121 
Excavation  of  the  barrows,  98 


Fabre,  M.,  on  the  instincts  of  Sphex,  93 

Farrer,   Mr.    T.    H.,   on   the  Koman    villa  at  Abinger, 

178-188 
Fat  eaten  by  worms,  36 
Fields  formerly  ploughed,  292 
Fish,  Mr.,  criticisms  on  my  views,  6 
Flints,  standing  vertically  in  the  residue  over  the  chalk, 

138 
acted  on  externally  and  internally  by  atmospheric 

agencies,  245 
Flowing  down  of  castings,  261 
Fluid,  digestive,  of  worms,  37 


INDEX.  319 

Food  of  worms,  leaves,  35 

earth,  100 

Foster,  Michael,  on  the  pancreatic  ferment,  37 
on  the  acidity  of  the  contents    of  the 

intestines,  52 
Foundations,  deep,  of  the  Eoman  buildings  at  Wroxeter, 

227 
Furrows  on  old  ploughed  fields,  292 


Galton,  Mr.,  on  the  number  of  dead  worms,  14 
Geikie,  Archibald,  on  Denudation,  238 

controverts  E.  de  Beaumont's  views  on 

Denudation,  289 

,  James,  controverts  Richthofen's  views,  237 

on  glaciated  rocks,  245 


Geographical  distribution  of  worms,  120 
Gizzards  of  worms,  246 
Glands,  calciferous,  17,  43 

function  of,  49 

Glen  Roy,  evidence  of  rarity  of  debacles,  260 


Haast,  Von,  on  aboriginal  instruments  in  New  Zealand 

found  buried,  147 
Hearing,  sense  of,  26 
Heat,  perception  of,  25 
Heaths,  inhabited    by   few    worms,  except  where  patha 

cross  them,  10 
Hensen  on  the  number  of  worms  in  gardens,  5 

on  worms  not  subsisting  on  earth,  108 

depth  of  burrows,  110 

on  number  of  worms  living  in  a  given  area,  158 

on  the  composition  of  mould,  238 

—  on    the    amount    of     humus    formed    by     two 

worms,  310 


320  INDEX. 

HensloWj  Prof.,  on  ledges  on  hill-sides,  278 
Hoffineister,  number  of  species  of  worms,  9 

on  worms  liybernating  in  company,  34 

perception  of  light  by  worms,  20,  22 

on  the  enemies  of  worms,  62 


—  depth  of  burrows,  110 

on  hybernation  of  worms,  114 


Hooker,  Sir  J.,  on  ledges  of  earth  on  the  Himalaya,  278 
Humus  acids,  action  of  on  rocks,  240,  244 

Instinct  of  worms,  35 
Intelligence  of  worms,  35,  64 
Intestines  of  worms,  their  contents  acid,  51 
Islands,  inhabited  by  worms,  120 

Johnson,  Dr.  H.,  on   the  Eoman    remains    at   "Wroxcter, 
222-228 

on  ammonia  in  worm-castings,  242 

Johnson,  S.  W.,  '  How  Crops  Feed,'  242 
Joyce,  Rev.  J.  G.,  on  the  Eoman  remains  at  Silchester,  201 
Jiilien,  Mr.  A.  A.,  on  the  composition  of  peat,  238 
on  the  humus  acids,  240,  244 

Key,  Eev.  H.,  on  the  burial  of  cinders  by  worms,  146 
King,  Dr.,    on    the    formation    of   mould   in  forests    in 
France,  5 

on  castings  near  Kice,  106,  117 

on    great  castings    on    the   Nilgiri  MouDtainfl 


and  in  Ceylon,  126 

weight  of  castings  near  Nice,  163 

on    disintegrated    castings    on    the    Corniche 


road,  276,  281 

on  the  washing  away  of  the   castings  r^n  the 


Nilgiri  Mountains,  274 


INDEX.  S2I 

Knole  Park,  beech- woods,  worms  absent,  12 
Koninck,  De,  on  the  disintegration  of  rocks,  235 


Laburnum  leaves,  67 

Land,  denudation  of,  230 

Lankester,  Eay,  on  the  structure  of  worms,  18 

on  worms  from  Kerguelen  Land,  121 

La  Plata,  dust  storms  of,  236 

Layard,  Mr.,  on  the  habits  of  the  cobra,  94 

Leaves,  worms  distinguish  the  taste  of  different  kinds,  82 

consumed  by  worms,  35 

their  decay  not  hastened  by  the  alkaline  secretion 

with  which  they  are  bathed,  38 

decayed,  generate  acids,  50 

used  in  plugging  up  burrows,  65 

used  to  line  burrows,  112 


Ledges  of  earth  on  hill- sides,  278 
Leon,  R,  on  the  digestive  fluid  of  worms,  38 
Light,  perception  of,  by  worms,  20 
Lime,  carbonate,  concretions  of,  45 


Maer  Hall,  amount  of  earth  brought  to  surface,  130 
Mallett,  Mr,,  on  the  sinking  of  the  ground  under  great 

buildings,  158 
Meat,  raw,  eaten  by  worms,  36 
Mental  qualities  of  worms,  34 
Mint,  leaves  of,  only  nibbled,  33 
Mississippi,  drainage  area  of,  233 
Mobius  on  the  habits  of  a  pike,  94 
Moniligaster,  246 

Morren  on  worms  surviving  long  immersion,  13 
'■ —  on  worms  lying  motionless  near  mouths  of  their 

burrows,  15 


822  INDEX. 

MorrcD  on  worms  eating  sugar,  36 

on  the  disappearance  of   the  calciferous  glands 

during  winter,  48 

on  stones  in  tlie  gizzards  of  worms,  247,  249 


Mould,  thickness  of,  annually  ejected  by  worms,  169 

thickness  of,  over  Koman  remains  at  Ohedworlli, 

199 
nature  and  thickness  of,  over  the  Koman  remains 

at  Silchester,  218 

'  thickness  of,  at  Wroxeter,  223 

formation  and  thickness  of,  over  the  chalk,  297 


Mountains,  worms  absent  from,  12 

Miiller,  Fritz,  on  the  worms  in'  South  Brazil,  121 


Nice,  castings  near,  106 

disintegrated  castings  near,  276 

Night,  worms  leave  their  burrows,  14 
Nilgiri  Mountains,  castings  on,  126 


Objects  strewed  on  the  surface  soon  buried  under  cast 

ings,  130 
Obliteration  of  old  furrows  on  ploughed  land,  292 
Odours,  degree  of  sensitiveness  to,  by  worms,  29 


Pancreatic  secretion,  37 

■ not  acid,  53 

Paper,  triangles  of,  82 

Path,  paved,  burial  of,  by  worm-castings,  146 

Paths  inhabited  by  worms,  10 

Pavement,  modern,  undermined  by  worms,  192 

Pavements,  ancient,  subsidence  of,  at  Silchester,  212 

Peat,  formati'.m  of,  239 

Percolation  of  earth  into  the  chalk,  297 


INDEX.  323 

Perichaeta,  naturalized  near  Nice,  106 
Perrier,  worms  surviving  long  immersion,  13 

on  tlie  calciferous  glands,  44 

— —  on  tlie  action  of  the  pharynx,  56 

on  the  burrowing  power  of  worms,  99 

on  naturalized  worms,  106 

on  worms  killed  by  acetic  acid,  159 

on  the  gizzards  of  worms,  246,  249 

Petioles  of  Clematis,  77 

of  the  ash,  79 

Pharynx,  action  of,  56 

Pike,  stupidity  of,  94 

pine-leaves  used  in  plugging  up  burrows,  58,  70 

lining  burrows,  112 

Pipes,  formation  of,  in  the  chalk,  137 
Playfair  on  Denudation,  290 
Ploughed  fields,  old,  292 
Plugging  up  of  the  burrows,  58 

■ use  of  the  process,  62 

Prehension,  power  of,  by  worms,  56 

Qualities,  mental,  of  worms,  34 


Ramsay,  Mr.,  on  the  sinking  of  a  pavement  undermined  by 
worms,  192 

on  Denudation,  231 

Remains,  ancient,  buried  by  worms,  176 

Rhododendron  leaves,  69 

Eichthofen  on  dust  deposits  in  China,  237 

Eobinia,  petioles  of,  81 

Hocks,  disintegration  of,  aided  by  worms,  240 

triturated  in  the  gizzards  of  worms,  249 

Eolling  down  of  dry  castings,  275 

Romanes,  Mr.,  on  the  intelligence  of  animals,  95 


324  INDEX. 

Sachs  on  living  roots  corroding  rocks,  243 

Sage,  leaves  of,  not  eaten  by  worms,  33 

Saliva,  doubtful  whether  any  secreted  by  worms,  42 

Saussure,  H.  De,  on  brick-pebbles,  254 

Schmulewitsch  on  the  digestion  of  cellulose,  37 

Scott,  Mr.  J.,  on  worms  near  Calcutta,  123 

Seeds  preserved  in  the  burrows  of  worms,  115 

Semper  on  various  animals  swallowing  sand,  102 

Senses  of  worms,  19 

Silchester,  old  Roman  town,  201 

Silica,  colloid,  acted  on  by  the  humus  acids,  242 

Sinking  of  the  pavemente  at  Silchester,  212 

Sites  inhabited  by  worms,  9 

Smell,  sense  of,  29 

Social  feelings  of  worms,  34 

Sorby,    Mr.,   on    the   trituration   of  small   particles   of 

rock,  257 
Starch  eaten  by  worms,  36 
digestion  of  the  granules  in  the  cells  of  leaves, 

41 
St.  Catherine's  Hill,  near  Winchester,  302 
Stones,  great,  undermined  by  worms  at  Leith  Hill  and  at 

Stonehenge,  148 

■ small,  heaped  over  burrows,  60 

small,  in  the  gizzards  of  worms,  247 

rounded  in  tlie  gizzards  of  worms,  249 

Stonehenge,    great    stones    of,    undermined    by    worms, 

154 

circular  trenches  near,  287 

Structure  of  worms,  16 

Subsidence  of  the  pavements  at  Silchester,  212 

Suction,  power  of,  56 

Sugar  eaten  by  worms,  36 

Summary  of  whole  book,  305 

Surface,  objects  strewed  on,  buried  under  castings,  130 


INDEX.  325 

Taste,  power  of,  32 

Thickness  of  the  layer  of  mould  annually   ejected  by 

worms,  169 

' of  the  mould  over  the  remains  at  Ched  worth,  199 

— ^ of  the  mould  over  the  remains  at  Silchester,  218 

— of  the   mould   over   the   Roman    remains    at 

Wroxeter,  223 
Thyme,  leaves  of,  not  eaten  by  worms,  38 
Touch,  worms  highly  sensitive  to,  28 
Triangles  of  paper,  82 
Trituration  of  particles  of  reck  in  the  gizzards  of  wormSj 

249 
Tumuli,  ancient,  290 
Tylor,  Mr.  A.,  on  Denudation,  233 
Tylor,  Mr.  E.,  on  anciently  ploughed  land,  293 
Typhosolis,  19 

Utricularia,  bladders  of,  109 

Vibrations,  worms  sensitive  to,  27 
Vision,  power  of,  in  worms,  20 

Walls,  ancient,  at  Abinger,  penetrated  by  worms,  188 

penetrated  by  worms  at  Silchester,  209 

Washing  away  of  castings,  272 

Wedgwood,  Mr.,  on  the  formation  of  mould,  3 

Weight  of  earth  ejected  from  a  single  burrow,  160 

Whitaker,  Mr.,  on  Denudation,  232 

White,  on  worms  leaving  their  burrows  at  night,  14 

Winchester,  chalk  formation  near,  301 

Wind,  action  of,  on  castings,  283 

Worms,  nocturnal,  13 

large  numbers  occasionally  die,  14 

dead  eaten  by  other  worms,  36 


326  INDEX. 

Worms,  contents  of  intestines,  acid,  51 

their  castings,  acid,  52 

power  of  suction,  56 

plugging  up  their  burrows,  58 

— intelligence  of,  64 

—  formation  of  their  burrows,  98 

number  of,  living  in  a  given  area,  158 

penetrating  ancient  walls,  188,  209 

gizzards  of,  and  the  trituration  of  the  contained 

stones,  246 

prefer  to  live  in  fine  earth,  291 


Wright,  Mr.,  on  the  age  of  Wroxeter,  221 
Wroxeter,  old  Eoman  to^n  of,  221 


DATE  DUE 

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